CHAP. VIII. OF THE ANIMALCULA INFUSORIA. (continued 2)

It appears plainly from the foregoing experiments, that when the blighted grains of wheat have been kept a long time, and the bodies of these animalcula are consequently become extremely dry, the rigidity of their minute vessels requires to be relaxed very gently, and by exceeding slow degrees; for we find that, on the application of water immediately to the bodies of these animalcula, when taken from the dry grains, they do not so certainly revive, as they do if the grains themselves be either buried in earth, or steeped in water for some time before they are taken out: the reason of which most probably is, that too sudden a relaxation bursts their delicate and tender organs, and thereby renders them incapable of being any more employed to perform the actions of life; and, indeed, there are always some dead ones amongst the living, whose bodies appear bursten, or lacerated, as well as others that lie extended and never come to life.

Some discretion is needful to adapt the time of continuing the grains in water or earth to the age and dryness of them; for if they be not opened before they have been too much or too long softened, the animalculum will not only seem dead, but will really be so. Of the two grains mentioned to have been four years old when put to soak, one was opened after it had lain thirty-six hours, and the event proved as already related; the other was suffered to lie for above a week, on opening which, all the anguillulæ near the husk were found dead, and seemingly in a decayed condition; but great numbers issued alive from the middle, and moved themselves briskly. Unless the husks be opened to let these creatures out after being steeped, they all inevitably perish; and when taken out and preserved in water, if the husks be left with them, they will die in a few days; but otherwise, continue alive in water for several months together; and, should the water evaporate, may be revived again by giving them a fresh supply.

72. Vibrio Linter.

V. ventricoso-ovatus, collo brevissimo. Ventricose oval vibrio, with a short neck.

This is one of the larger animalcula, of an egg-shape, pellucid, inflated, somewhat depressed at top; the apex is prolonged into a moveable crystalline neck, the belly is replete with pellucid molecules. It is not very common, though occasionally to be found among the lemnæ.

73. Vibrio Utriculus.

V. teres, antice angustatus truncatus, postice ventricosus. Round vibrio, the fore-part narrow and truncated, the lower ventricose.

It does not ill resemble a bottle in shape; the belly is replete with molecular intestines, the neck bright and clear, the top truncated; in some a pellucid point is visible at the bottom of the belly. It is in an unceasing, vehement, and vacillatory motion, the neck moving from one side to the other as fast as possible.

74. Vibrio Fasciola.

V. antice attenuatus, medio latiusculus, postice acutus. Vibrio with a small fore-part, the middle a little bigger, the hind-part acute.

This is a pellucid animalculum, in the middle are the intestines in the form of points; an alimentary pipe, which lessens gradually in size, is also perceptible. The motion of it is quick, darting itself up and down in the water with great velocity. It is found in water just loosened from the frost, and seldom elsewhere.

75. Vibrio Colymbus.

V. crassus, postice acuminatus, collo subfalcato. Thick vibrio, sharpened at the end, the neck a little bent.

It is larger than most of the vibrios, and not unlike a bird in shape. The neck is round, shorter than the trunk, of an equal size throughout, and of a bright appearance, the apex obtuse. The trunk is thick, somewhat triangular, full of yellow molecules; the fore-part broad, the hinder-part acute, the motion slow.

76. Vibrio Strictus.

V. elongatus linearis, anticem versus attenuatus, apice obtuso. Vibrio lengthened out almost to a line, small towards the fore-part, the apex obtuse.

The body linear, being a bright membranaceous thread, without any flexure; the hind-part somewhat thicker, round, and filled with molecules, excepting just at the end, where there is a small pellucid empty space. The apex is obtuse, and rather globose; it has a power of contracting and drawing in the filiform part.

77. Vibrio Anas.

V. oblongus, utroque fine attenuatus, collo cauda longiore. Oblong vibrio, both ends attenuated, the neck longer than the tail.

The trunk is oblong, opake, and filled with molecules. Both the fore and the hind-part is prolonged into a pellucid talky membrane, which the animalculum has a power of retracting at pleasure. The tail is more acute than the neck. It is most generally found in salt water; a species of them have been found in river water, with a longer neck.

78. Vibrio Cygnus.

V. ventricosus, collo adunco. Corpulent vibrio, with a crooked neck.

This animalculum is little more than a most pellucid line, crooked at top, prominent in the middle, and sharp at the end; the fore-part, or neck, is equal in length to the rest of the body, and three times longer than the hind-part or tail; the intermediate part swelling out, is full of dark-coloured molecules and pellucid intestines. It is very small, and the most slothful of all those which move and advance their necks.

79. Vibrio Anser.

V. ellipticus, collo longo, tuberculo dorsali. Plate XXV. Fig. 27 and 29. Elliptical vibrio, with a long neck, and a little lump on the back.

It is between the vibrio proteus and vibrio falx, and is distinguished by the lump b, Fig. 29, on the back, placed behind the neck; from this an even long neck, a, proceeds. The trunk, d, is elliptic, round, and without any lateral inequality; full of molecules, the hind-part, e, sharp and bright, the fore-part produced into a bending neck that is longer than the body; the apex even and whole, with blue canals passing between the marginal edges, occupying the whole length of the neck; in one of them a vehement descent of water to the beginning of the trunk is perceivable. The motion of the body is slow, that of the neck is more lively and flexuous, sometimes spiral. It is found in water where duck-weed grows.

80. Vibrio Olor.

V. ellipticus, collo longissimo, apice nodoso. Plate XXV. Fig. 28. Elliptical, with a very long neck, and a knob on the apex.

The form of the body is elliptical and ventricose, the hind-part somewhat sharp. It is membranaceous, dilatable, winding variously; the hind-part is sometimes replete with darkish molecules. The neck, d, is three or four times longer than the body, of an equal size throughout, except a small degree of thickness at the apex, f, very pellucid. The motion of its neck is very lively, that of the body slow. It is found in water that has been kept for a long time, and which has acquired a vegetable greenness.

81. Vibrio Falx.

V. gibbosus, postice obtusus, collo falcato. A gibbous vibrio, the hind-part obtuse, the neck crooked.

The body is pellucid, elliptical, the fore-part lessening into a little round bright neck, nearly of the same length as the trunk, the hind-part obtuse. The trunk itself is rather rounding or tending to the gibbous, and filled with very small molecules; there are also two bright globules, one within the hind extremity, the other in the middle of the body. The neck being immoveable, the motions of the animalculum somewhat resemble those of a scythe.

82. Vibrio Intermedius.

V. membranaceus, antice attenuatus, postice subacutus. Membranaceous vibrio, the fore-part small, the hinder part somewhat acute.

It seems to be an intermediate species between the preceding vibrio and the fasciola, No. 74; it is a thin membrane, constantly folded. The whole of it has a crystalline talky appearance, the middle replete with grey particles of different sizes; it has all round a distinct bright margin; the apex of the neck is truncated, the tail obtuse.

VI. CYCLIDIUM.

Vermis inconspicuus, simplicissimus, pellucidus, complanatus, orbicularis vel ovatus. A simple, invisible, flat, pellucid, orbicular or oval worm.

83. Cyclidium Bulla.

C. orbiculare hyalinum. Orbicular bright cyclidium.

A very pellucid white animalculum, or orbicular skin, the edges a little darker than the rest. By the assistance of the compound microscope, some globular intestines of a very crystalline appearance are just perceptible. Its motion is slow and semicircular. It is found occasionally in an infusion of hay.

84. Cyclidium Milium.

C. ellipticum crystallinum. Elliptic and crystalline cyclidium.

It is very pellucid, of a crystalline splendour, membranaceous and elliptical; a line may be perceived through the whole length of it, a point in the fore-part, the hinder-part getting darker. Its motion is swift, fluttering, and interrupted; probably both extremities are ciliated.

85. Cyclidium Fluitans.

C. ovale crystallinum. Oval crystalline cyclidium.

This is one of the smallest animalcula. The body of an oval, or rather suborbicular shape, depressed, crystalline; two small blue spaces may be discovered by the assistance of the microscope at the sides of this little creature.

86. Cyclidium Glaucoma.

C. ovatum, interaneis ægre conspicuis. Oval cyclidium, the intestines perceived with difficulty.

A pellucid oval body, with both ends plain, or an oval membrane, with a distinct well-defined edge; the intestines are so transparent that they can scarce be discerned, when it is empty; when full, they are of a green colour, and there are dark globules discoverable in the middle.

In plenty of water it moves swiftly in a circular and diagonal direction; whenever it moves slowly it seems to be taking in water, the intestines are then also in a violent commotion. Two of the smaller ones may often be perceived cohering to each other, and drawing one another by turns; nor are they separated by death, for they remain united even when the water is evaporated. Those who are not familiar with these kinds of observations, may easily mistake the shade in a single one for a junction of two, or the junction of two for a copulation, for they generate by division.

87. Cyclidium Nigricans.

C. oblongiusculum, margine nigricans. Oblong cyclidium, with a black margin.

It is very small, pellucid, and flat. With a small magnifier, it may be mistaken for an enchelis.

88. Cyclidium Rostratium.

C. ovale, antice mucronatum. An oval cyclidium, the fore-part pointed.

This is an oval, smooth, and very pellucid animalculum, with the fore-part running out into an obtuse point; with this it seems to feel and examine the bodies which it approaches. It is probably ciliated, though the hairs have not been discovered.

The intestines are filled with a blue liquor, forming in a tube, which, from the aperture to the middle of the body, is divided into two legs or branches; beyond the middle there are two little transverse blue lines. This colour sometimes vanishes, and then they seem to be composed of vesicles.

89. Cyclidium Nucleus.

C. ovale, postice acuminatum. An oval cyclidium, the hind-part pointed.

The body is pellucid, depressed, the fore-part obtusely convex, the hind-part acute, the intestines vesicular, the fore and hind-part on each side dark. It resembles a grape-seed.

90. Cyclidium Hyalinum.

C. ovatum, postice acutum. Oval cyclidium, the hind-part acute.

This cyclidium is oval, flat, and bright, without any visible intestines, the hinder-part somewhat smaller than the fore-part; it has a tremulous kind of motion.

91. Cyclidium Pediculus.

C. ovale convexum, subtus planum. An oval convex cyclidium, the bottom even. Trembley Polyp. 1, p. 282.

This is a gelatinous white animalculum, the bottom gibbous over the back, the extremities depressed and truncated, with one end sometimes apparently cloven into two; perhaps this is the aperture of the mouth. It is scarce ever seen but on the arms and the body of the hydra pallida, upon which it runs as if it had feet.

92. Cyclidium Dubium.

C. ovale, supra convexum, subtus cavum. Oval cyclidium, the upper part convex, the under part concave.

This is one of the larger species, the margin is pellucid, and the inner part contains a great number of black molecules.

VII. PARAMÆCIUM.

Vermis inconspicuus, simplex, pellucidus, membranaceus, oblongus. An invisible, simple, membranaceous, flat, and pellucid worm.

93. Paramæcium Aurelia. Volvox Terebella. Ellis.

P. compressum, versus anticem plicatum, postice acutum. Compressed paramæcium, oblong, folded towards the fore-part, the hinder-part acute.

This is rather a large animalculum, membranaceous, pellucid, and four times longer than it is broad; the fore-part obtuse, transparent, without intestines; the hind-part replete with molecules of various sizes; the fold, which goes from the middle to the apex is a striking characteristic of the species, forming a kind of triangular aperture, and giving it somewhat the appearance of a gimblet. Its motion is rectilinear, reeling or staggering, and generally vehement.

They are frequently found cohering lengthwise; the lateral edges of both bodies appear bright. They may also sometimes be seen lying on one another alternately, at others, adhering by the middle. They will live many months in the same water without its being renewed. They are to be found in June in ditches where there is plenty of duck-weed.

94. Paramæcium Chrysalis.

P. cylindraceum, versus anticam plicatum, postice obtusum. Plate XXV. Fig. 26. Cylindrical paramæcium, folded towards the fore-part, the hinder-part obtuse.

It differs very little from the preceding, only the ends, a b, are more obtuse, and the margins filled with black globules. It is an inhabitant of salt water.

95. Paramæcium Versutum.

P. cylindraceum, postice incrassatum, utraque extremitate obtusum. Cylindrical paramæcium, the lower part thick, and both ends very obtuse.

An oblong, green, and gelatinous body, filled with molecules; the lower-part thick, the fore-part smaller, both ends obtuse, and may be seen to propagate by division. It is found in ditches.

96. Paramæcium Oviferum.

P. depressum, intus bullis ovalibus. Plate XXV. Fig. 25. Depressed paramæcium, with large oval molecules withinside.

A membranaceous, oval, oblong animalculum, grey and pellucid, having many oval very pellucid corpuscles, a, dispersed about the body, and many black grains towards b.

97. Paramæcium Marginatum.

P. depressum, griseum, margine duplici. Plate XXV. Fig. 24. Depressed paramæcium, grey, with a double margin.

This is one of the largest of the class, flat, elliptical, every part filled with molecules, except in the lower end, b, where there is a pellucid vesicle; this animalculum is surrounded by a broad double margin; when expiring, a bright spiral intestine is observable. a, the apex; b, the vesicle; c, the spiral intestine.

VIII. KOLPODA.

Vermis inconspicuus, simplicissimus, pellucidus, complanatus, sinuatus. An invisible, very simple, pellucid, flat and crooked worm.

98. Kolpoda Lamella.

K. elongata, membranacea, antice curvata.

This animalculum resembles a long, narrow, and pellucid membrane, the hind-part obtuse, narrower, and curved towards the top; no intestines discoverable, only a ridge or fold going through the middle. Its motion is reeling or staggering, and very singular, moving to and fro on its edge, not on the flat side, as is usual with most microscopic animals. It is found in water, but is very seldom to be met with.

99. Kolpoda Gallinula.

K. oblonga, dorso antico membranaceo hyalino. Oblong kolpoda, the back towards the fore-part bright and membranaceous.

The apex rather bent; the belly oval, convex and striated. It is found in fetid salt water.

100. Kolpoda Rostrum.

K. oblonga, antice uncinata. Oblong, the fore-part hooked.

The fore-part is bent into a kind of hook; the hind-part is obtuse, and everywhere filled with black molecules. One of the edges from the fore-part to the middle, is often so blunted and dilated, that the rest of the body appears quite smooth, and that part thick and triangular. It has a slow and horizontal motion. It is to be found, though but seldom, in water where the lemnæ grow.

101. Kolpoda Ochrea.

K. elongata, membranacea, apice attenuato, basi in angulum rectum producta. Long kolpoda, membranaceous, the apex attenuated, the base bent in a right angle to the body.

A large animalculum, long, and of a singular figure, depressed, membranaceous, flexible; one edge nearly straight, the other somewhat bent, filled with obscure molecules, and a few little bladders dispersed here and there; the apex bright and small, the base projecting like the human foot from the leg.

102. Kolpoda Mucronata.

K. membranacea dilatata, antice angustata, altero margine incisa. Membranaceous, dilated kolpoda, the fore-part smaller than the hind-part, with a small incision at one side.

This animalculum is a dilated bright membrane; the apex an obtuse point, with a broad marked border running entirely round it; within the margin it is filled with grey molecules, a fleshy disc on one side, which terminates in a splendid little point on the other side the disc. It has a truncated appearance.

103. Kolpoda Triquetra.

K. obovata depressa, altero margine retuso. Kolpoda nearly of an egg-shape, one edge turned back.

This animalculum appears to consist of two membranes; the upper side flattened, the lower convex; the apex is bent so as to form a kind of shoulder. It was found in salt water.

104. Kolpoda Striata.

K. oblonga, subarcuata depressa, candida, antice acuminata, postice rotundata. Oblong, somewhat of a pear-shape, white, the fore-part pointed, the hind-part round.

It is very pellucid and white, the upper part rather bent, and terminating in a point, the lower part obtusely round; at the apex or mouth there is a little black pellucid vesicle; when a very great magnifying power is used, the body appears covered with long streaks; the lower extremity is furnished, like many other animalcula, with very small globules. It is to be found in salt water.

105. Kolpoda Nucleus.

K. ovata, vertice acuto. Egg-shaped kolpoda, with an acute vertex.

It is of an oval shape, the vertex pointed, of a brilliant transparency, which renders the viscera visible; they consist of a number of round diaphanous vesicles.

106. Kolpoda Meleagris.

K. mutabilis, antice uncinata, postice complicata. Plate XXV. Fig. 22. Changeable, with the fore-part like a hook, the hind-part folded up.

A most singular animalculum of the larger species; it has a dilated membrane, with the finest folds, which it varies and bends in a moment; the fore-part of the body to the middle is clear and bright, the hind-part variously folded in transverse elevated plaits, and full of molecules; the apex turned into a hook, the margin sinuous, and beneath the apex denticulated with three or four teeth; but in some which are more beautifully wrought, the edge is obtusely notched, and set with still smaller notches; in the hind-part there are twelve or more equal pellucid globules. It moves sometimes in a straight, at other times in a crooked line, a, the hooked apex; b, the denticulated margin; c, the series of globules; d, the folded part at bottom.

107. Kolpoda Assimilis.

K. depressa, non plicatilis apice uncinato, margine antico ad medium, usque crenulato postice, dilatato acutiusculo. Depressed kolpoda, the apex turned in the form of a small hook; the margin of the fore-part notched from the top to the middle, the lower part swells out, then diminishes again into a short point. It has an elliptic mass in the middle, but is never folded like the preceding. It was found on the sea coast.

108. Kolpoda Cucullus.

K. ovata, ventricosa, infra apicem incisa. Plate XXV. Fig. 23. Egg-shaped, ventricose, with an incision in the fore-part.

It is very pellucid, with a well-defined margin, filled with little bright vesicles, differing in size, and of no certain number. Its figure is commonly oval, the top bent into a kind of beak, seldom an acute one, sometimes oblong, but most usually obtuse. Its intestines are formed of from eight to twenty-four bright little vesicles, not conspicuous in such as are young. Some have supposed these to be animalcula which the kolpoda had swallowed, but Müller is of opinion that they are its offspring. In some only one crystalline vesicle occupies the middle of the body. It moves in general with great vivacity, and in all directions. When this creature is near death in consequence of the evaporation of the water, it protrudes its offspring with violence. It is found in infusions of vegetables, and in fetid hay. In some few a transparent membranaceous substance may be perceived projecting beyond the beak, and resembling an exuvia; the same may also be observed in the enchelis and vibrio: it is, therefore, possible that these animalcula cast their skin, as is the case with many of the class of insects. a shews the cap or hood, b the incision.

109. Kolpoda Cucullulus.

K. oblonga, infra apicem oblique incisa. Oblong kolpoda, with an oblique incision a little below the apex.

A very pellucid crystalline animalculum; it is furnished with several pellucid globules; there is a bending a little beneath the top, which in some positions is very distinctly seen, in others not. It was observed in an infusion of the sonchus arvensis.

110. Kolpoda Cucullio.

K. ovalis depressa, infra apicem tantillum sinuata. Flat oval kolpoda, with a small degree of bending beneath the apex.

This is an oval, or rather an elliptical kolpoda, membranaceous and bright; flat on the upper side, and convex on the under; the fore-part is clear, and from the middle to the hinder-part it is filled with silver-like globules. It frequently stretches out the fore-part, and folds it in different positions.

111. Kolpoda Ren.

K. crassa medio sinuata. This kolpoda is thick, and carved in the middle.

The body is yellow, thick, and rather opake; curved a little, in the middle, so as to have the appearance of a kidney; the whole body is filled with molecules. Its motion is quick, fluctuating, and interrupted. When the water in which it swims is about to fail, it assumes an oval form, is compressed, and at last bursts. It is found in an infusion of hay, generally about thirteen hours after the infusion is made.

112. Kolpoda Pirum.

K. convexa, ovalis, apice in rostrum producta. Plate XXV. Fig. 20 and 21. Convex kolpoda, oval, the apex formed into a kind of beak.

The body is uniform and transparent, without any sensible inequality; the neck rather long and a little bent; it is of a pale colour, and furnished with obscure little globules. It propagates by division. Fig. 20 represents this animalculum; Fig. 21, the same dividing to form another; a, the fore-part; b, the hind-part; c, where it is dividing.

113. Kolpoda Cuneus.

K. clavata, teres, apice dentata. Clavated kolpoda, round, the apex dentated.

This is a large animalculum, the body white, gelatinous, without any distinct viscera. It has a pellucid, bright, striated pustule on one side of the fore-part; the apex is distinguished by three or four teeth, the hinder-part is smaller than the fore-part, with an obtuse termination, which it can bend into a spiral form.

IX. GONIUM.

Vermis inconspicuus, simplicissimus, complanatus, angulatus. An invisible, simple, smooth, angular worm.

114. Gonium Pectorale.

G. quadrangulare, pellucidum moleculis sedecim sphæricis. Plate XXV. Fig. 17. This gonium is quadrangular, pellucid, with sixteen spherical molecules.

These sixteen little oval bodies are nearly equal in size, of a greenish colour, pellucid, and set in a quadrangular membrane, like the jewels in the breast-plate of the high-priest, reflecting light on both sides. Its animality is evinced by its spontaneous motion, advancing alternately towards the right and left; these little bodies seem oval when in motion, round when at rest; the four interior ones are a little larger than the rest. It is found in pure water.

115. Gonium Pulvinatum.

G. quadrangulare, opacum pulvillis quatuor. Quadrangular, opake, with four little pillows.

This appears like a little quadrangular membrane, plain on both sides; with a large magnifier it looks like a bolster, formed of three or four cylindric pillows, flattened or sunk here and there. Thus it appeared to Müller on the first examination; some days after all the sides were plain, without any convexity, and divided into little square spaces by lines crossing each other. It is found upon dunghills.

116. Gonium Corrugatum.

G. quadrangulare, albidum, medio correptum. Quadrangular gonium, white, sunk a little in the middle.

It is somewhat of a square shape, very minute, without any visible viscera, a little depressed in the middle. It is found in various infusions; in some positions it appears streaked.

117. Gonium Rectangulum.

G. rectangulum, dorso arcuato. This gonium is rectangular, the hind-part arched.

This differs but little from the preceding; the angle at the base is a right one, the larger vesicle is transparent, the rest green.

118. Gonium Truncatum.

G. obtusangulum, postice arcuatum. Gonium with obtuse corners, the hind-part arched.

Much larger than the foregoing, the fore-part is a straight line, with which the sides form obtuse angles, the ends of the sides being united by a curved line; the internal molecules are of a dark green, there are two little bright vesicles in the middle; its motion is languid. It is found chiefly in pure water, and that but seldom.

X. BURSARIA.

Vermis simplicissimus, membranaceus, cavus. A very simple, hollow, membranaceous worm.

119. Bursaria Truncatella.

B. ventricosa, apice truncata. Ventricose bursaria, the top truncated.

An animalculum that is visible to the naked eye, white, oval, and truncated at the top, where there is a large aperture descending towards the base; most of them have four or five yellow eggs at the bottom. It moves itself at pleasure from right to left, and from left to right, ascending to the surface of the water in a right line, and sometimes rolling about while descending.

120. Bursaria Bullina.

B. cymbæformis, antice labrata. Boat-shaped bursaria, the fore-part formed into a lip.

A pellucid crystalline animalculum, furnished with splendid globules of different sizes swimming about within it; the under-side convex, the upper side hollow, the fore-part forming a kind of lip.

121. Bursaria Hirundinella.

B. utrinque laciniata, extremitatibus productis. Plate XXV. Fig. 19.

Bursaria with two small projecting wings, which give it somewhat of the appearance of a bird, and it moves something like a swallow. It is invisible to the naked eye, but by the microscope appears to be a pellucid hollow membrane; no intestines are visible. a, the head; b, the tail; c, one of the wings.

122. Bursaria Duplella.

B. elliptica, marginibus inflexis. Plate XXV. Fig. 18. Elliptic bursaria with the edge bent in and out.

A crystalline membrane folded up, without any visible intestines, if we except a little congeries of points under one of the folds. It was found among duck-weed.

123. Bursaria Globina.

B. sphærica, medio pellucentissima. Spherical bursaria, very pellucid in the middle.

A subspheric hollow animalculum, the lower end furnished with black molecules of various sizes, the fore-part with obscure points, the rest entirely empty, and the middle very pellucid; it moves slowly from right to left.

XI. CERCARIA.

Vermis inconspicuus, pellucidus, caudatus. An invisible pellucid worm with a tail.

124. Cercaria Gyrinus.

C. rotundata, cauda acuminata. Round cercaria, with a sharp tail.

It has a white gelatinous body, without any traces of intestines; the fore-part somewhat globular, the hind-part round, long, and pointed; sometimes it appears a little compressed on each side. When swimming, the tail is in a continual vibration, like that of a tadpole. It seems very similar to the spermatic animalcula.

125. Cercaria Gibba.

C. subovata, convexa, antice subacuta, cauda tereti. Somewhat of an oval shape, convex, the fore-part rather acute, the tail round.

It is a small animalculum, gelatinous, white, opake, and without any visible intestines; the upper part convex or gibbous; many of them were found in infusions of hay, as well as of other vegetables.

126. Cercaria Inquieta.

C. mutabilis, convexa, cauda lævi. Plate XXV. Fig. 31 and 32. Changeable convex cercaria, with a smooth tail.

This animalculum so often changes the form of its body, that it is not easy to describe it; it is sometimes spherical, sometimes like a long cylinder, at other times of an oval figure, white and gelatinous; the tail is filiform and flexible, the upper part vibrating vehemently; no visible viscera; a pellucid globule may be observed at the base, and two very small black points placed near the top at d, Fig. 32; whether they be eyes to the animalculum is not known. It was found in salt water. a, Fig. 31, the body; b, the tail.

127. Cercaria Lemna.

C. mutabilis, subdepressa, cauda annulata. Plate XXV. Fig. 33, 34, and 35. Mutable cercaria, somewhat flattened, with an annulated tail.

This animalculum varies its form so much, that it might be mistaken for the proteus of Baker, though, in fact, it is totally different. The body sometimes appears of an oblong, sometimes of a triangular, and sometimes of a kidney shape. The tail is generally short, thick, and annulated, but sometimes long, flexible, cylindric, and without rings; vibrating, when stretched out, with so much velocity, that it appears as it were double. The intestines are not very distinct; a small pellucid globule, which Müller supposes to be its mouth, is observable at the apex; and two black points not easily discovered, he thinks are its eyes; sometimes it draws the tail entirely into the body. It walks slowly after taking three or four steps, and extends the tail, erecting it perpendicularly, shaking and bending it; in which state it very much resembles a leaf of the lemna. Fig. 33, a, the body rather spherical; b, the tail. Fig. 34, c, the triangular body; b, the tail. Fig. 35, the body extended; e e, the eyes; f f, the intestines; g, a large vesicle; h, a smaller one.

128. Cercaria Turbo.

C. globulosa, medio coarctata, cauda uniseta. Plate XXV. Fig. 30. Globular cercaria, the middle contracted, with a tail like a bristle.

Partly of an oval, and partly of a spherical shape, pellucid, and of a talky appearance. It seems to be composed of two globular bodies, the lowermost of which is the smallest; this figure is occasioned by the contraction at the middle. There are two black points, like eyes, even with a transverse line which crosses the upper part of this little creature; several large globules may also be discerned; the tail is sometimes quite straight, sometimes turned back on the body. It is to be found among duck-weed.

129. Cercaria Poduria.

C. cylindracea, postice acuminata subfissa. Plate XXV. Fig. 36 and 37. Cylindric cercaria, the hind-part sharp and somewhat cloven.

It resembles the young ones of the podura[126] which live among the lemnæ, is pellucid, and appears to consist of a head, trunk, and tail; the head resembles that of a herring; the trunk is cylindric, replete with black spiral intestines, and appears more or less extended, at the will of the animal; nothing is to be discovered in the hinder-part. The tail most commonly appears to be divided into two bristles. The intestines are in a continual motion when the body moves, and by reason of their various shades give it a very rough appearance; some lateral hairs or cilia are likewise to be perceived. When it moves, it revolves at the same time as upon an axis. It is to be found in November and December, in marshy places that are covered with the lemna. Fig. 36, a, the head; b, the trunk; c, the tail; d, with one point; it is seen at e, Fig. 37, with two points; f, the hairs on the side.

130. Cercaria Viridis.

C. cylindracea mutabilis, postice accuminata fissa. Cylindrical cercaria, mutable, the lower end sharp, and divided into two parts.

This animalculum in some of its states considerably resembles the last, but has a much greater power of changing its shape. It is naturally cylindrical, the lower end sharp, and divided into two parts; but it sometimes contracts the head and tail so as to assume a spherical figure, at other times it projects outwards. It is found in the spring, in ditches of standing water.

131. Cercaria Setifera.

C. cylindracea, antice angustior, postice acuminata. Cylindric cercaria, the fore-part smallest, the hind-part pointed.

This is a small cercaria, the body rather opake, and of a round figure. The upper part is bright, and smaller than the rest; the trunk is more opake; the tail sharp, and near it a little row of short hairs. It has a slow rotatory motion. It is found in salt water, though but seldom.

132. Cercaria Hirta.

C. cylindrica, antice subtruncata, postice obtusa, bimucronata. Cylindrical cercaria, the fore-part somewhat truncated, the lower part obtuse, finishing with two small points.

A cylindrical opake animalculum, with two small points at the lower end, moveable, yet rigid, and placed at some distance; when in motion, the body appears to be surrounded with rows of small hairs separated a little from each other. It was observed in salt water.

133. Cercaria Crumena.

C. cylindraceo-ventricosa, antice oblique truncata, cauda lineari bicuspidata. Cylindrical, ventricose cercaria, the fore-part obliquely truncated, the tail linear, terminating with two diverging points.

The body is ventricose, cylindrical, thick, and wrinkled; the lower part small, the upper part terminates in a small, straight neck, like that of a pitcher; the tail terminates in two diverging points.

134. Cercaria Catellus.

C. tripartita, cauda bisecta. Three-parted cercaria, the tail divided into two parts.

This animalculum is more complex in its form than many others; it has a moveable head, which is affixed to the body only by a point; an abdomen, which is not so wide, but twice as long as the head, replete with intestines; and a tail which is shorter than the head, narrower than the belly, and terminating in two bristles, which it can unite and separate at pleasure. It moves with vivacity, though without going far from its own place.

135. Cercaria Catelina.

C. tripartita, cauda bicuspidata. Cercaria distinguished into three parts, with a short forked tail.

It differs from the preceding in several respects, being larger, the body thicker, and more cylindrical; the lower part truncated, with two short diverging points projecting from the middle. It was found in a ditch containing plenty of duck-weed.

136. Cercaria Lupus.

C. cylindrica, elongata, torosa cauda spinis duabus. Plate XXV. Fig. 39. Cylindric cercaria, long, the tail furnished with two spines.

This animalculum is larger than most of the cercarias, and in some particulars resembles the vorticella. It is full of muscles, capable of being contracted or extended; cylindric, composed of a head, a trunk, and a tail; the head is larger than the body, the apex turned down into a little hook; the tail is like the body, but narrower, terminating in two very bright spines, which it extends in different directions; sometimes it contracts itself into one half its common size; and again extends itself as before. It was found in water among duck-weed. a the head, b the trunk, c the tail, d d the spines thereof.

137. Cercaria Vermicularis.

C. cylindrica annulata, proboscide exsertili, cauda spina duplici. Plate XXV. Fig. 40. Cylindrical, annulated, with a projecting proboscis, two small spines for the tail.

It is a long, cylindrical, fleshy, mutable animalculum, divided into eight or nine rings, or folding plaits; the apex either obtuse or notched into two points; the hind-part rather acute, and terminating in two pellucid thorns, between which a swelling is sometimes perceived. It often projects a kind of cloven proboscis. It is found in water where duck-weed grows. d d the points of the fore-part, e the proboscis.

138. Cercaria Forcipata.

C. cylindrica, rugosa, proboscide forcipata exsertili, cauda bicuspidata.

Cylindrical cercaria, wrinkled, with a forked proboscis, which it can extend, or retract. It is found in marshy situations.

139. Cercaria Pleuronectes.

C. orbicularis, cauda uniseta. Orbicular, the tail consisting of one bristle.

It is membranaceous, rather round, and white. In the fore-part are two blackish points; the hind-part is furnished with a slender sharp tail; it has orbicular intestines of different sizes in the middle; the largest of them are bright. Its motion is staggering or wavering; in swimming it keeps one edge of the lateral membrane upwards; the other folded down. It is found in water which has been kept for several months.

140. Cercaria Tripos.

C. subtriangularis, brachiis deflexis, cauda recta. Plate XXV. Fig. 38. Cercaria somewhat of a triangular form, two bent arms, and a straight tail.

The body is flat, pellucid, and triangular, having each angle of the base or fore-part bent down into two linear arms; the apex of the triangle is prolonged into a tail. It was found in salt water; b, the tail; a a, the bent arms.

141. Cercaria Cyclidium.

C. ovalis, postice subemarginata, cauda extersili. This is oval, the hind-part somewhat notched, with a tail that it thrusts out at pleasure.

It has an oval, smooth, membranaceous, and pellucid body, with a black margin. The tail is not fixed to the edge, but concealed under it, and comes out from it at every motion, but in such a manner, as to project but little from the edge. There is also a kind of border to the hinder-part. Its intestines are very pellucid vesicles. It is frequently found in pure water.

142. Cercaria Tenax.

C. membranacea, antice crassiuscula, truncata, cauda triplo breviore. Membranaceous, the fore-part rather thick, truncated, the tail three times shorter.

It is an oval, pellucid membrane, something larger than the monas lens. The fore-edge is thick and truncated, the hinder-part acute, and terminating in a short tail. It whirls about in various directions with great velocity.

143. Cercaria Discus.

C. orbicularis, cauda curvata. A small orbicular animalculum, with a bent tail.

144. Cercaria Orbis.

C. orbicularis, seta caudali duplici longissima. Orbicular cercaria, with a tail consisting of two very long bristles.

145. Cercaria Luna.

C. orbicularis, cauda lineari duplici brevi. This is likewise orbicular, with two short spines for a tail; the fore-part hollowed, so as to form a kind of crescent.

XII. LEUCOPHRA.

Vermis inconspicuus, pellucidus, undique ciliatus. An invisible worm, pellucid, and everywhere ciliated.

146. Leucophra Conflictor.

L. sphærica, subopaca, interaneis mobilibus. Spherical opake leucophra, with moveable intestines.

This animalculum, or rather a heap of animalcula, is larger than most species of the vorticella; it is perfectly spherical, and semi-transparent, of a yellow colour, the edges dark. It rolls at intervals from right to left, but seldom removes from the spot where it is first found. It is filled with a number of the most minute molecules, which move as if they were in a violent conflict. In proportion to the number of these little combatants, which are accumulated either on one side or the other, the whole mass rolls either to the right or left, the molecules going in the same direction; it is then tranquil for a short time, but the conflict soon becomes more violent, and the sphere moves the contrary way in a spiral line. When the water begins to fail, they assume an oblong, oval, or cylindric figure; the hind-part of some being compressed into a triangular shape, and the transparent part escaping as it were from the intestines, which continue to move with the same violence till the water wholly fails, when the molecules are spread into a shapeless mass, which also soon vanishes, and the whole shoot into a form, having the appearance of crystals of sal ammoniac, as figured by Baker. Empl. for the Micros. Plate III. No. 3.

147. Leucophra Mamilla.

L. sphærica, opaca, papilla exsertili. Sphærical opake leucophra, with a small papillary projection.

It is of a dark colour, and filled with globular molecules, the short hairs are curved inwards; and it occasionally projects and retracts a little white protuberance. It is not uncommon in marshy water.

148. Leucophra Virescens.

L. cylindracea, opaca, postice crassiore. Cylindrical, opake, leucophra, the lower part much thicker than the upper part.

This is a large, pear-shaped, greenish coloured animalculum, filled with opake molecules, and covered with short hairs; generally moving in a straight line. It is found in salt water.

149. Leucophra Viridis.

L. ovalis opaca. Oval, opake leucophra.

Though at first sight it may be taken for a variety of the leucophra virescens; yet, on a further examination, it differs in many particulars; it cannot lengthen and shorten itself as that does. It is also much smaller. Sometimes it appears contracted in the middle, as if it were about to be divided in two.

150. Leucophra Bursata.

L. viridis, ovalis, antice truncata. Green oval leucophra, the fore-part truncated.

This is similar in many respects to the foregoing leucophra; it is of a long oval shape, bulging in the middle, and filled with green molecules; every where ciliated, except at the apex, which is truncated, and shaped somewhat like a purse; the hairs larger, and sometimes collected in minute fasciculi. It is to be found in salt water.

151. Leucophra Posthuma.

L. globularis, opaca, reticulo pellucenti. This is globular and opake, covered as it were with a pellucid net. It was found in fetid salt water.

152. Leucophra Aurea.

L. ovalis, fulva, utraque extremitate æquali obtusus. Oval yellow leucophra, both ends of it equally obtuse.

The little hairs are discovered with difficulty; it has, in general, a vehement rotatory motion.

153. Leucophra Pertusa.

L. ovalis, gelatinosa, apice truncato obtusa altera latera suffossa. Oval gelatinous leucophra, the apex obtusely truncated, one side sunk down.

Gelatinous, yellow, and small, without any molecules; the forepart is truncated, the hind-part brought nearly to a point, with a kind of oval hole on one side. It was found in salt water.

154. Leucophra Fracta.

L. elongata, sinuato angulata subdepressa. Leucophra long, with sinuated angles, rather flat.

The body is white, gelatinous, and granulated; it changes its form considerably.

155. Leucophra Dilatata.

L. complanata, mutabilis, marginibus sinuatis. Smooth changeable leucophra, with a sinuated edge.

A gelatinous membrane, with a few grey molecules in the forepart, and a great number in the hinder-part; it is sometimes dilated into a triangular form, with sinuated sides; at other times the shape is more irregular and oblong.

156. Leucophra Scintillans.

L. ovalis, teres, opaca, viridis. Oval, round, opake, green leucophra.

This animalculum is supposed to be ciliated, from its bright twinkling appearance, which probably arises from the motion it gives the water; it is nearly of an egg-shape. It was found in December among the lemna minor.

157. Leucophra Vesiculifera.

L. ovata, interaneis vesicularibus. Plate XXV. Fig. 41. Oval leucophra, with vesicular intestines.

An animalculum that is a kind of mean between the orbicular and oval, very pellucid, with a defined dark edge and inside, containing some very bright vesicles, or bladders. The middle frequently appears blue, and the vesicles seem as if set in a ground of that colour. Müller could never perceive any of those rays which are mentioned by Spallanzani; he confesses, however, that he once saw an individual like this environed with very small unequal shining rays.

158. Leucophra Globulifera.

L. crystallina, ovato-oblonga. Crystalline leucophra, of an oblong oval shape.

The body is round, very pellucid, without molecular intestines, though at one edge it has three little pellucid globules; it is everywhere set with short hairs. It was found in a ditch where the lemna minor grew.

159. Leucophra Pustulata.

L. ovato oblonga, postice oblique truncata. An oblong oval leucophra, the lower end obliquely truncated.

The body is white, gelatinous, and somewhat granulated; the lower part truncated, as if an oblique section were made in an egg near the bottom. It is covered with little erect shining hairs; at the lower extremities a few bright pustules may be discovered. It is found in marshy waters.

160. Leucophra Turbinata.

L. inverse conica, subopaca. Leucophra in shape like an inverted cone, and rather opake.

It is a round pellucid body, somewhat of the shape of an acorn, with a pellucid globule at the lower end. It was found in fetid salt water.

161. Leucophra Acuta.

L. ovata, teres, apice acuto, mutabilis, flaviscans. Oval leucophra, round, with the apex acute, mutable, yellow.

This is gelatinous, thick, and capable of assuming different shapes; the apex bright, and the rest of the body filled with innumerable little spherules; sometimes it draws itself up into an orbicular shape, at other times one edge is sinuated. It was found in salt water.

162. Leucophra Notata.

L. ovata, teres, puncto marginali atro. Oval leucophra, round, with a black point at the edge.

163. Leucophra Candida.

L. hyalina, oblonga, altera extremitate attenuata, curvata. Leucophra of a talky appearance, oblong, one end smaller than the other, and bent back.

The body membranaceous, flat, very white, with no visible intestines, except two oval bodies which are with difficulty perceptible; the whole edge is ciliated. Found in an infusion with salt water.

164. Leucophra Nodulata.

L. ovato-oblonga, depressa, serie nodulorum duplici. An oblong oval species of leucophra, with a double row of little nodules.

165. Leucophra Signata.

L. oblonga, subdepressa. Oblong, subdepressed leucophra, with a black margin, filled with little molecular globules, but more particularly distinguished by a curved line in the middle, something in the shape of a long S; one end of which is at times bent into the form of a small spiral. It is common in salt water, in the months of November and December.

166. Leucophra Trigona.

L. crassa, obtusa, angulata, flava. Thick, obtuse, angular, and yellow leucophra.

A yellow, triangular mass, filled with unequal pellucid vesicles, one of which is much larger than the rest, and the edge surrounded with short fluctuating hairs. It was found in a marshy situation, but is not common.

167. Leucophra Fluida.

L. subreniformis, ventricosa. Leucophra somewhat of a kidney shape, but ventricose.

168. Leucophra Fluxa.

L. sinuata reniformis. Reniform, sinuated leucophra.

169. Leucophra Armilla.

L. teres annularis. Round annular leucophra.

170. Leucophra Cornuta.

L. inverse conica, viridis opaca. Plate XXV. Fig. 42 and 43. An inverted cone, green, opake.

It bears some resemblance to the vorticella polymorpha, No. 290, and the vorticella viridis, No. 283, and requires to be observed for some time before its peculiar characters can be ascertained; the body is composed of molecular vesicles, of a dark green colour; for the most part it is like an inverted cone, the fore-part being wide and truncated, with a little prominent horn or hook on both sides; the hind-part conical, everywhere ciliated, the hairs exceedingly minute; those in the fore-part are three times longer than the latter, and move in a circular direction. The hinder-part is pellucid, and sometimes terminates in two or three obtuse pellucid projections. The animalculum will at one moment appear oval, at another reniform, and ciliated at the fore-part; but at another time the hairs are concealed. When the water evaporates, it breaks or dissolves into molecular vesicles. It is found late in the year in marshy grounds. Fig. 42, a, the hinder-part pointed; g, the cilia; h h, the sides. Fig. 43, b, the hinder-part obtuse; e, the fore-part; f, the horns.

171. Leucophra Heteroclita.

L. cylindrica, antice obtusa, postice organo cristato duplici exsertili. Plate XXV. Fig. 44 and 45. Cylindrical leucophra, the fore-part obtuse, the hind-part furnished with a double-tufted organ, which it can thrust in or out at pleasure. To the naked eye it appears like a white point; in the microscope, as a cylindrical body, the fore-part obtusely round, the middle rather drawn in, the lower-part round, but much smaller than the upper-part. With a large magnifying power the whole body is found to be ciliated. The intestines are very visible. It is represented in Fig. 44 as it generally appears; a, the fore-part; b, the hind-part; d, the hooked intestines; in Fig. 45, with the plumed organs; i i, the plumes; g g, the sheaths from which they are projected.

XIII. TRICHODA.

Vermis inconspicuus, pellucidus, crinitus. An invisible, pellucid, hairy worm.

172. Trichoda Grandinella.

T. sphærica, pellucida, superne crinata. Spherical, pellucid, the upper-part hairy.

A most minute pellucid globule, the intestines scarce visible, the top of its surface furnished with several short bristles, which are not easily distinguished, as the animalculum has a power of extending and withdrawing them in an instant. It is found in pure water, and in infusions of vegetables.

173. Trichoda Cometa.

T. sphærica, antice crinita, globulo appendente. Plate XXV. Fig. 46 and 47. Spherical, the fore-part hairy, with an appendant globule.

It is a pellucid globule, replete with bright intestines, the fore-part furnished with hairs, the hind-part with a pellucid appendant globule.

174. Trichoda Granata.

T. sphærica, centro opaco peripheria crinita. Plate XXV. Fig. 48. Spherical, with an opake center, the periphery hairy.

It resembles the trichoda grandinella and trichoda cometa just described. It has a darkish nucleus in the center; its intestines are imperceptible; short hairs on the edge.

175. Trichoda Trochus.

T. subpiriformis, pellucida, antice utrinque crinita. Trichoda somewhat of a pear-shape, pellucid, each side of the fore-part distinguished by a little bunch of hairs.

176. Trichoda Gyrinus.

T. ovalis, teres, crystallina, antice crinita. Oval, round, crystalline trichoda, the front hairy.

It is one of the smallest among the trichoda, the body smooth and free from hairs, except at the fore-part, where there are a few. It is found in salt water.

177. Trichoda Sol.

T. globularis, undique radiata. Plate XXV. Fig. 65 and 66. Globular trichoda, everywhere radiated.

This splendid creature constitutes a new genus, but as we know of no more of the same kind, it is introduced here. It is a little crystalline round corpuscle, the upper part convex; it is beset with innumerable diverging rays, which are longer than the diameter of the body, proceeding from every part of its surface: the inside is full of molecules. The body contracts and dilates, but the animalculum remains confined to the same spot. It was found with other animalcula in water which had been kept for three weeks. It propagates by division, and is represented as dividing in Fig. 66.

178. Trichoda Solaris.

T. sphæroidea, peripheria crinita. Spheroidal trichoda, with a few hairs round the circumference.

The body is orbicular, bright, and filled with globular intestines; in many, a moveable substance, something like the letter S, may be discovered; it has hairs, seldom exceeding seventeen in number, which are disposed round the circumference, each of them nearly equal in length to the diameter of the animalculum.

179. Trichoda Bomba.

T. mutabilis, antice pilis sparsis. Plate XXV. Fig. 67 and 68. Changeable, with a few hairs dispersed on the fore-part.

It is a thick animalculum, larger than the trichoda granata, No. 174, and of a yellow colour; pellucid, and replete with clay-like molecules; it is very lively, moving about with so much velocity, as to elude the sharpest sight and most pertinacious observer, and assuming various shapes, sometimes appearing spherical, sometimes reniform, or kidney-shaped, sometimes as at Fig. 67.

180. Trichoda Orbis.

T. orbicularis, antice emarginata crinita. Orbicular, the fore-part notched and hairy.

It in some, respects resembles the former, but is larger. It is composed of vesicular molecules; is of a spherical figure, smooth, pellucid, and a little notched in the fore-part. The notched part is filled with long hairs, but there are none on the rest of the body.

181. Trichoda Urnula.

T. urceolaris, antice crinita. Plate XXV. Fig. 64. This trichoda is in the form of a water pitcher, the fore-part hairy.

A membranaceous pellucid animalculum, the hind-part obtuse, the middle something broader, the fore-part truncated, filled with vesicular black molecules; the hairs in the fore-part are even and short. Its motion is slow.

182. Trichoda Diota.

T. urceolaris, antice angustata, ora apicis utrinque crinita. Pitcher-shaped trichoda, the fore-part smallest; the upper part of the mouth hairy at the edges.

The body is of a clay-colour, and filled with molecules; the upper-part cylindrical and truncated, the lower part spherical.

183. Trichoda Horrida.

T. subconica antice latiuscula, truncata postice obtusa, setis radiantibus cincta. Trichoda somewhat of a conical form, the fore-part rather broad and truncated, the lower-part obtuse, and the whole covered with radiating bristles.

184. Trichoda Urinarium.

T. ovata, rostro brevissimo crinito. Egg-shaped, with a short hairy beak.

185. Trichoda Semiluna.

T. Semiorbicularis, antice subtus crinita. Semiorbicular, the fore-part hairy underneath.

A smooth pellucid animalculum, and shaped like a crescent.

186. Trichoda Trigona.

T. convexa, antice ciliata, postice erosa. Plate XXV. Fig. 63. Convex, the fore-part ciliated, the hind-part as it were gnawed off.

This is a triangular animalculum, a little convex on both sides, the fore-part acute, the hind-part a little broader. A notch is seen at a, in the hind-part; b, the ciliated fore-part; c, a tube.

187. Trichoda Tinea.

T. clavata, antice crinita, postice grossa. This is clubbed, the fore-part hairy, the hind-part large.

This animalculum is round, not very pellucid, narrow in the fore-part, and resembling an inverted club; it is also like some of the tinea.

188. Trichoda Nigra.

T. ovalis compressa, antice latior crinita. Oval, compressed trichoda, the fore-part broader and hairy.

The body is opake, when in violent motion it is black, when at rest one side is pellucid; the middle of the fore-part is furnished with little moveable hairs. It was found in salt water.

189. Trichoda Pubes.

T. ovato-oblonga gibba, antice depressa. Plate XXV. Fig. 61 and 62. An egg-shaped oblong bunch, the fore-part depressed.

An animalculum with a bunch above the hind-part, marked with black spots, depressed towards the top, a little folded, and somewhat convex underneath; at least this is its appearance when in motion. Very minute hairs occupy the apex, but they are seldom visible till the creature is in the agonies of death, when it extends and moves them vehemently from an arched chink at top, apparently endeavouring to draw in the last drop of water. It is found in water where the duck-weed grows, chiefly in December. b, the hairs; c, the black globules; a, the projecting bunch.

190. Trichoda Floccus.

T. membranacea, antice subconica, papillis tribus crinitis. Membranaceous trichoda, the fore-part rather conical; three small papillæ project from the base, which are set with hairs.

191. Trichoda Sinuata.

T. oblonga depressa, altero margine sinuato crinita, postice obtusa. An oblong depressed trichoda, one margin hollow and hairy, the lower end obtuse.

The intestines seem to be more lymphatic than molecular; it is of a yellow colour, and the hollow edge ciliated. It was found in river water.

192. Trichoda Præceps.

T. membranacea, sublunata, medio protuberante, extorsum crinita. Membranaceous trichoda, somewhat lunated, protuberant in the middle, a row of hairs on the outside.

A pellucid membrane, the fore-part formed into a kind of neck, one edge rising into a protuberance like a hump-back, the other edge convex.

193. Trichoda Proteus.

T. ovalis, postice obtusa, collo elongata retractile, apice crinito. Plate XXV. Fig. 56, 57, 58, 59, 60. Oval trichoda, the lower-part obtuse, with a long neck, which it has a power of contracting or extending.

Baker in his Employment for the Microscope, p. 260-266, dignifies this animalculum with the name of proteus, on account of its assuming a great number of different shapes, so as scarce to be known for the same animal in its various transformations; and, indeed, unless it be carefully watched while passing from one shape to another, it will often become suddenly invisible.

When water, wherein any kinds of vegetables have been infused, or animals preserved, has stood quietly for some days or weeks in a glass or other vessel, a slimy substance will be collected about the sides, some of which being taken up with the point of a penknife, placed on a slip of glass in a drop of water, and viewed through the microscope, will, be found to harbour several kinds of little animals that are seldom seen swimming about at large. The insect we are treating of is one of these, and was discovered in such slime-like matter taken from the side of a glass jar, in which small fishes, water-snails, and other creatures had been kept. Its body in substance and colour resembled that of a snail; the shape thereof was somewhat elliptical, but pointed at one end, whilst from the other proceeded a long, slender, and finely proportioned neck, terminated with a head, of a size perfectly suitable to the other parts of the animal.

194. Trichoda Versatilis.

T. oblonga, postice acuminata, collo retractili, infra apicem crinito. Oblong trichoda, the hind-part acute, with a neck that it can extend or contract at pleasure, the under-part of the extremity of the neck hairy.

It resembles in some measure the trichoda proteus just described, but the neck is shorter, the apex less spherical, and the hinder part of the trunk acute. It lives in the sea.

195. Trichoda Gibba.

T. oblonga, dorso gibbera, ventre excavata, antice ciliata, extremitatibus obtusis. Plate XXV. Fig. 55. Oblong trichoda, with a bunch on the back, the belly hollowed out, the fore-part ciliated, both ends obtuse.

The body is pellucid, the upper part swelled out, within it are numerous obscure molecules, and three large globules, the ends rather incline downwards; when the water begins to fail, a few minute hairs may be discovered about the head and at the abdomen; the body then becomes striated longitudinally.

196. Trichoda Foeta.

T. oblonga, dorso protuberante, antice ciliata, extremitatibus obtusis. Oblong trichoda, with the back protuberant, the fore-part ciliated, both ends obtuse.

The body is round and long, and when extended somewhat resembles a rolling-pin in shape; both ends are obtuse, and one shorter than the other; it can draw in the ends and swell out the sides, so as to appear almost spherical.

197. Trichoda Patens.

T. elongata, teres, antice foveata, fovæ marginibus ciliata. Plate XXV. Fig. 54. This trichoda is long, round, in the fore-part it has a long hole, the edges of which are ciliated.

It is a long cylindrical animalculum, filled with molecules; the fore-part bright and clear, with a long opening, a, near the top, which tapers to a point, and is beset with hairs. It is found of different lengths in salt water.

198. Trichoda Patula.

T. ventricosa, subovata, antice canaliculata, apice et caniculo crinito. Big-bellied, rather inclining towards an oval figure, with a small tube at the fore-part, the upper-end of which is covered with hairs.

199. Trichoda Foveata.

T. oblonga, latiuscula, antice corniculis micantibus, postice mutica. Oblong trichoda, rather broad, three little horns on the fore-part, the hinder-part beardless.

200. Trichoda Striata.

T. oblonga, altero margine cursum, sinuata et ciliata, utraque extremitate obtusa. Oblong trichoda, one edge rather curved, and also furnished with a row of hairs; both extremities obtuse.

It is a splendid animalculum, of a fox colour, and at first sight might be taken for a kolpoda. The body is oblong, the lower end somewhat larger than the other, the body becoming smaller at that part where the hairs commence; it has a set of streaks which run from one end to the other, and at the abdomen a double row of little eggs, lying in a transverse direction. It was found in river water in December.

201. Trichoda Uvula.

T. planiuscula elongata, æqualis, antice crinita. Plate XXV. Fig. 53. Rather flat and long, of an equal size throughout, the fore-part hairy.

This animalculum is six times longer than broad, round, flexuous, and of an equal size; the greater part filled with obscure molecules; the fore-part, a, rather empty, distinguished by an alimentary canal, and lucid globules near the middle, c; short hairs occupy the margin of the fore-part, some are dispersed into a chink near the canal. It is found in an infusion of hay and other vegetables.

202. Trichoda Aurantia.

T. subsinuata, ovata, antice patula, apice ad medium crinita. Trichoda somewhat sinuated, oval, the fore-part broad, the apex hairy to the middle.

It is of a gold colour, pellucid, and filled with a variety of vesicles.

203. Trichoda Ignita.

T. ovata, apice acuminata, subtus fulcata, fulco crinito. Oval trichoda, the apex rather acute, the under-part furrowed, the furrows hairy.

It is of a fine purple gold colour, somewhat of a reddish cast, pellucid, splendid, with a number of globules of different sizes; the fore-part small, the hind-part obtuse, and having a very large opening, which appears to run through the body.

204. Trichoda Prisma.

T. ovata, subtus convexa, supra in carinam compressa, antice angustior. Oval trichoda, the under part convex, the upper part compressed into a kind of keel, the fore-part small.

It is very small, and so transparent that it cannot easily be delineated; its form is singular, and no hairs can be observed.

205. Trichoda Forceps.

T. ovalis, antice forcipata, cruribus inæqualibus crinitis. Oval trichoda, with a pair of forceps at the fore-part, with unequal hairy legs.

A large animalculum, somewhat depressed, of a pellucid yellow colour, and filled with molecules; in the lower part there is a black opake globule, the fore-part is divided into long lobes, one of which is falciform and acute, the other dilated, and obliquely truncated; both the apex and the edge of these are furnished with hairs of different lengths; it can open, shut, or cross these lobes at pleasure; by this motion of them it appears to suck in the water. It was found about the winter solstice in water, covered with lemnæ.

206. Trichoda Forfex.

T. ventrosa, antice forcipata, postice papilla duplici instructa. Round and prominent trichoda, the fore-part formed into a kind of forceps, and two small protuberances.

One of the forceps of this animalculum is twice as long as the other, hooked, and ciliated. It was found in river water.

207. Trichoda Index.

T. obovata, margine antico subtus crinito, alteroque apicis in degitum producto. Obovated trichoda, the under part of the front of the margin hairy, the apex is formed by the fore-part, projecting like the finger on a direction-post. It was found in salt water.

208. Trichoda S.

T. striata, antice ciliata, extremitatibus in oppositum flexis. Striated trichoda, the fore part ciliated, the extremities bent in opposite directions.

A yellow animalculum, formed of two pellucid membranes, striated longitudinally; the lower end is obliquely truncated.

209. Trichoda Navicula.

T. triquetra, antice truncata ciliata, postice acuta prominula. Three-cornered trichoda, the fore-part truncated and ciliated, the hind-part acute, and bent a little upwards.

It has a crystalline appearance, rather broad, the under side towards the hinder-part convex, the fore-part broad, the apex nearly a straight line, the bent end pointed and turned upwards; and a kind of longitudinal keel running down the middle.

210. Trichoda Succisa.

T. ovalis depressa, margine crinito, postice in crura inæqualia erosa. Flattened oval trichoda, the edge hairy, the hinder part hollowed out so as to form two unequal legs.

211. Trichoda Sulcata.

T. ovato-ventricosa, apice acuminata, fulco ventrali, utrinque crinito. Ovated ventricose trichoda, the apex acute, with a furrow at the abdomen, and both sides of it ciliated.

212. Trichoda Anas.

T. elongata, apice colli subtus crinito. Plate XXV. Fig. 49. Long, the apex of the neck underneath hairy.

A smooth animalculum, five times broader than it is long, filled with darkish molecules; it has a bright neck, b c; under the top of the neck at d a few unequal hairs are perceptible. Its motions are languid. It is found in pure water.

213. Trichoda Barbata.

T. elongata, teres, subtus ab apice ad medium crinita. Long trichoda, round, the under part from the apex to the middle hairy.

This animalculum is round, somewhat linear, with both ends obtuse; the fore-part narrower, forming as it were a kind of neck, under which is a row of fluctuating hairs. The trunk is full of grey molecules.

214. Trichoda Farcimen.

T. elongata, torulosa, setulis cincta. Plate XXV. Fig. 50 and 52. Long and thick trichoda, surrounded with small bristles.

The body is long, round, pellucid, and covered with very minute hairs; it has also a great number of mucid vesicles about the body.

215. Trichoda Crinita.

T. elongata, teres, undique ciliata, subtus ad medium usque crinita. Long trichoda, round, everywhere ciliated on the upper part, and the under part likewise hairy as far as the middle.

216. Trichoda Angulus.

T. angulata, apice crinita. Angular, the apex hairy.

This animalculum is long, more convex than most of the genus, divided by a kind of articulation into two parts equal in breadth, but of different lengths, the fore-part being shorter than the hind-part; the apex furnished with short waving hair, indistinct molecules withinside, no hair on the hind-part.

217. Trichoda Linter.

T. ovato oblonga, utraque extremitate prominula. Plate XXV. Fig. 51. The shape of an oblong egg, with prominences at both extremities.

Both extremities of the body are raised, so that the bottom becomes convex, and the upper part depressed like a boat. It varies in shape at different ages, and sometimes has a rotatory motion. It is found in an infusion of old grass.

218. Trichoda Paxillus.

T. linearis depressa, antice truncata crinitaque, postice obtusa. Linear flat trichoda, the fore-part truncated and hairy, the hinder-part obtuse.

A long animalculum, full of grey molecules; the fore-part rather smaller than the hind-part, and furnished with minute hairs. It was found in salt water.

219. Trichoda Vermicularis.

T. elongata, cylindracea, collo brevi, apice crinito. Plate XXVII. Fig. 1. Long cylindrical trichoda, with a short neck, the apex hairy.

Gelatinous, the fore-part pellucid, the hind-part full of molecules. It was found in river water. It is represented in different appearances in the figure; a, the neck; b, the hairs; c, a little vesicle in the hinder-part.

220. Trichoda Melitœa.

T. oblonga, ciliata, colli dilatabilis, apice globoso, pilifero. Plate XXVII. Fig. 3. Oblong ciliated trichoda, with a dilatable neck, the apex globular, and surrounded with hairs, the edge is ciliated, and a kind of peristaltic motion perceivable in it. It is found, in salt water, though but very rarely. a, the neck; b, the globular apex; c, the body ciliated.

221. Trichoda Fimbriata.

T. obovata, apice crinita, postice oblique truncata, serrata. Plate XXVII. Fig. 2. Obovated trichoda, the apex hairy, the hinder-part obliquely truncated and serrated.

222. Trichoda Camelus.

T. antice crinita, crassiuscula medio utrinque emarginata. Thick, and the fore-part hairy, with notches on the middle and each side.

The fore-part of the body is ventricose; the back divided by an incision in the middle into two tubercles; the lower part of the belly sinuated; its motions are languid. It is found, though not often, in vegetable infusions.

223. Trichoda Augur.

T. oblonga, vertice truncata, antico corporis margine, superne pedata, inferne setosa. The body is oblong, depressed, pellucid, and filled with molecules; the vertex truncated, the fore-part forming a small beak; underneath are three feet; beyond these, towards the hinder-part, it is furnished with bristles.

224. Trichoda Pupa.

T. cucullata, fronte crinita, cauda inflexa, This trichoda is hooded, the front hairy, the tail inflected.

The body is rather round, pellucid and consists of three parts; the head, which is broad, appears to be hooded, the top being furnished with very small hairs; a transparent vesicle occupies the lower region of the head; and over the breast from the base of the head is suspended a production resembling the sheath of the feet in the pupa of the gnat.

225. Trichoda Lunaris.

T. arcuata, teres, apice crinita, cirro, caudali inflexo. Arched trichoda, round, the apex hairy, the tail bent.

This animalculum is round and crystalline; the hind-part somewhat smaller than the fore-part; the intestines are with difficulty distinguished. The edge of the back and the part near the tail are bright and clear. It bends itself into the form of an arch.

226. Trichoda Bilunis.

T. arcuata, depressa, apice crinita, cauda biseta. Arched flattened trichoda, the apex hairy, and two little bristles proceeding from the tail.

227. Trichoda Rattus.

T. oblonga, carinata, antice crinita, postice seta longissima. Plate XXVII. Fig. 4. Oblong trichoda, with a kind of keel; the fore-part hairy, and a very long bristle proceeding from the hinder-part. a, the mouth; b, a small knob at the bending of the tail; c, the tail.

228. Trichoda Tigris.

T. subcylindrica, elongata, apice crinita, cauda setis duabus longis. This trichoda is long, and somewhat cylindrical, the apex hairy, the tail divided into two long bristles.

It resembles the former, but differs in the form of the tail, which consists of two bristles, and likewise in having a kind of incision in the body, at some little distance from the apex.

229. Trichoda Pocillum.

T. oblonga, antice truncata, crinita, cauda articulata, biseta. Plate XXVII. Fig. 5 and 6. Oblong trichoda, the fore-part truncated and hairy, the tail articulated, and divided into two bristles.

The body is cylindrical, pellucid, muscular, and capable of being folded up; it appears double; the interior part is full of molecules, with an orbicular muscular appendage which it can open and shut, and this forms the mouth. The external part is membranaceous, pellucid, dilated, and marked with transverse streaks; the animalculum can protrude or withdraw the orbicular membrane at pleasure. Some have four articulations in the tail, others five; and it has two pair of bristles, or projecting parts, one placed at the second joint, the other at the last. It has been frequently found in marshes. In Fig. 6 it is seen with the mouth open; in Fig. 5, with it shut, a a, the jaws; b b, the first bristles; c c, the second pair; d, the spine at the tail.

230. Trichoda Clavus.

T. antice rotundata, crinita, postice acuminato-caudata. The fore-part round and hairy, the hind-part furnished with a sharp tail. This animalculum has a considerable resemblance to a common nail.

231. Trichoda Cornuta.

T. supra convexa, subtus plana, apice crinita, cauda lineari simplici. Trichoda with the upper part convex, the under side plain, the apex hairy, the tail linear and simple.

To these characters we may add, that the body is membranaceous, elliptical, closely filled with molecules; the fore-part lunated, the hinder-part round, and terminating in a tail as long as the body.

232. Trichoda Gallina.

T. elongata, antice sinuata, fronte crinita, cauda pilosa. Long trichoda, the fore-part sinuated, the front hairy, the tail formed of small hairs.

It is of a grey colour, flat, with seven large molecules and globules within it, the front obtuse, and set with hairs; the hinder-part terminating in a tail formed of very fine hairs. It was found in river water.

233. Trichoda Musculus.

T. ovalis, antice crinita, postice subtus caudata. Plate XXVII. Fig. 7. Egg-shaped, the fore-part hairy, the tail projecting from the under part.

A smooth egg-shaped animalculum, with a double margin or line drawn underneath it; the fore-part narrow, and furnished with short hairs, which are continually playing about; underneath the hind-part is a small tail. It has molecular intestines, and moves slowly. It is found in infusions of hay which have been kept for some months, a, the head; b, the tail.

234. Trichoda Delphis.

T. clavata, fronte crinita, cauda acuminata, subreflexa. Clubbed trichoda, the front hairy, the tail small and rather bent upwards.

It is smooth and pellucid, having the fore-part dilated into a semicircle, gradually decreasing in breadth towards the tail; the front is hairy, the hairs standing as rays from the semicircular edge; one of these edges is sometimes contracted. It is to be found in river water.

235. Trichoda Delphinus.

T. oblonga, antice crinita, postice cauda reflexa truncata. Plate XXVII. Fig. 8. Oblong, the fore-part hairy; in the hind-part is the tail, which is turned back, the end of it truncated.

A pellucid, smooth, egg-shaped animalculum; the hind-part terminating in a tail about half the length of the body, dilated at the upper end, truncated, and always bent upwards.

In the inside are vesicles of an unequal size; it moves sometimes on its belly, sometimes on its side; the tail seldom varies its position. It was found in hay which had been infused for some months, a, the hairs on the fore-part; b, the tail.

236. Trichoda Clava.

T. clavata, fronte crinita, cauda reflexili. Club trichoda, the fore-part hairy, the tail turned back.

The fore-part is thick, the hind-part narrow; both extremities obtuse, pellucid, and replete with molecules; the hind-part bent down towards the middle.

237. Trichoda Cuniculus.

T. oblonga, antice crinita, postice subacuminata. Oblong, the fore-part hairy, the hind-part rather acute, filled with molecules and black vesicles.

238. Trichoda Felis.

T. curvata, grossa, antice angustior, postice in caudam attenuata, subtus longitudinaliter crinita. Plate XXVII. Fig. 9. Curved trichoda, large, the fore-part small, the hinder-part gradually diminishing into a tail; the under part set longitudinally with hairs. a, the head; b, the tail; c, the hairs.

239. Trichoda Piscis.

T. oblongata, antice crinita, postice in caudam exquisitam attenuata. Plate XXVII. Fig. 13 and 14. Oblong, the fore-part is hairy, the hind-part terminating in a very slender tail. It is smooth, pellucid, much longer than broad, but of nearly an equal breadth throughout, and filled with yellow molecules; the fore-part obtuse, the hind-part exquisitely slender and transparent; the upper side is convex. a, the fore-part; b, the tail.

240. Trichoda Larus.

T. elongata, teres, crinita, cuspidi caudali duplici. Long, round trichoda, surrounded with hairs, the tail divided into two points. See Zoologia Danica.

241. Trichoda Longicauda.

T. cylindracea, antice truncata et crinita, cauda elongata, biarticulata et biseta. Plate XXVII. Fig. 10. Cylindrical trichoda, the fore-part truncated and surrounded with hairs, the tail long, furnished with two bristles, and having two joints. a, the hairs at the mouth; d, the oesophagus; e, the articulation of the tail; f, the bristles.

242. Trichoda Fixa.

T. sphærica, peripheria crinita, pedicello solitario. Spherical trichoda; this has the circumference set with hairs, and a little solitary pedicle projecting from the body.

243. Trichoda Inquilinus.

T. vaginata, folliculo cylindrico hyalino, pedicello intra folliculum retortili. Sheathed trichoda, in a cylindrical transparent bag, having a little pedicle bent back within the bag. See Zool. Dan. prodr. addend. p. 281.

244. Trichoda Ingenita.

T. vaginata, folliculo depressa, basi latiore sessilis. Sheathed trichoda, the bag depressed, the base broadest.

The animalculum that is contained in this sheath is funnel-shaped, with one or more hairs, proceeding from each side of the mouth of the funnel. It can extend or contract itself freely in the bag, fixing its tail to the base, without touching the sides. It was found in salt water.

245. Trichoda Innata.

T. vaginata, folliculo cylindrico, pedicello extra folliculum. Plate XXVII. Fig. 11. Trichoda sheathed in a cylindrical bag, with a pedicle passing through and projecting beyond it. These characters distinguish it sufficiently from the preceding one. b, the animalculum in the sheath; d, the tail.

246. Trichoda Transfuga.

T. latiuscula, antice crinita, postice setosa, altero latere sinuata, altero mucronata. Broad trichoda, the fore-part hairy, the hinder-part full of bristles; one side sinuated, and the other pointed. See Zool. Dan. prod. addend. p. 281.

247. Trichoda Ciliata.

T. ventricosa, postice crinibus pectinata. Ventricose, the hinder-part covered with hair. See Zool. Dan. Icon. Tab. 73, Fig. 13, 15.

248. Trichoda Bulla.

T. membranacea, lateribus inflexis, antice et postice crinita. Membranaceous trichoda, the sides bent inwards; the fore and hind-part are both furnished with hairs.

249. Trichoda Pellionella.

T. cylindracea, antice crinita, postice setosa. Cylindrical, the fore-part hairy, the hinder-part furnished with bristles.

This trichoda is rather thick in the middle, and pellucid, with a few molecules here and there, the sides obtuse, the fore-part ciliated with very fine hairs, the hind part terminating in a kind of bristles.

250. Trichoda Cyllidium.

T. ovata, apice hiante, basique crinita. Plate XXVII. Fig. 15. Egg-shaped, the apex gaping, the base hairy.

Pellucid, the hinder extremity filled with globules of various sizes, the fore-part narrower, without any appearance of an external organ. It vacillates upon the edge, commonly advancing on its flat side, and continually drawing in water; it then gapes, and opens into a very acute angle, almost to the middle of the body; but this is done so instantaneously, that it is scarcely perceptible. a, the mouth; b, the hairs or bristles, which it extends when nearly expiring.

251. Trichoda Cursor.

T. ovata, antice crinita, postice duplici pilorum strictorum et curvorum fasciculo. Oval trichoda, the fore-part hairy, and the hinder-part also furnished with some straight and curved hairs in two fascicles.

The body is flat and filled with molecules; in the fore-part is an oblong empty space, into which we may sometimes see the water sucked in.

252. Trichoda Pulex.

T. ovata, antice incisa, fronte et basi crinita. Plate XXVII. Fig. 12. Egg-shaped, with an incision in the fore-part; the front and base hairy. a, the anterior part; b, the posterior part; c, the incision.

253. Trichoda Lynceus.

T. subquadrata, rostro adunco, ore crinito. Plate XXVII. Fig. 16. Nearly square, with a crooked beak, the mouth hairy.

At first sight it does not seem very dissimilar to some of the monoculi. The body is membranaceous, and appears compressed, stretched out into a beak above, the lower part truncated; under the beak is a little bundle of hairs; the lower edge bends in and out, and is surrounded with a few bristles. The intestines are beautifully visible, and a small bent tube goes from the mouth to them in the middle of the body; these, as well as the tube, are in frequent agitation. There is likewise another tube between the fore and hind edge filled with a blue liquor. a, the beak; b, the mouth; c, the base.

254. Trichoda Erosa.

T. orbicularis, antice emarginata, altero latere crinita, postice setosa. Orbicular trichoda, the fore-part notched; one side furnished with hairs, the hinder-part with bristles.

255. Trichoda Rostrata.

T. depressa, mutabilis, flavescens, ciliis longis setisque pediformibus. Depressed trichoda, mutable, yellow, with long ciliated hairs, and feet tapering to a point.

The figure of the body is generally triangular; the apex formed into an obtuse beak, which the animalculum sometimes draws in, so that it appears quite round; the feet are four in number, one of them is longer than the rest; both feet and hairs are within the margin. It is found in water where duck-weed has been kept.

256. Trichoda Lagena.

T. teres, ventricosa, rostro producta, postice setosa. Round ventricose trichoda, with a long neck, and the lower end set with bristles.

257. Trichoda Charon.

T. cymbiformis fulcata, antice et postice crinita. Plate XXVII. Fig. 17 and 18. Boat-shaped trichoda with furrows, the fore and hind-parts both hairy.

The body is oval; it resembles a boat as well in its motion as shape; the upper part is hollowed, the under part furrowed and convex; the stern round, with several hairs proceeding from it. It was found in salt water. Fig. 17, a, the head; b, the tail. Fig. 18, d, a pellucid bubble that is sometimes to be perceived.

258. Trichoda Cimex.

T. ovalis, marginibus lucidis, antice et postice crinita. Plate XXVII. Fig. 19. Oval trichoda, with a lucid margin, both the fore and hind-part hairy.

It is about the size of the trichoda lynceus, No. 253, has an oval body, with a convex back, flat belly, and an incision in the margin of the fore-part, the edges of which incision appear to be in motion. Its intestines are pellucid and ill-defined. When it meets with any obstacles in swimming, it makes use of four small bristles, which are fixed to the under side, as feet. a, the hairs in the fore-part; b, the bristles at the hind-part; d, the back; e, two small projecting hairs; f, the substance to which the animalculum has affixed itself.

259. Trichoda Cicada.

T. ovalis, marginibus obscuris, antice et subtus crinita, postice mutica. Oval trichoda, with an obscure margin, the fore-part covered with hairs on the under side, and the hinder-part beardless.

It does not differ considerably from the preceding, though Müller has pointed out some shades by which they may be discriminated.

XIV. KERONA.

Vermis inconspicuus corniculatus. An invisible worm with horns.

260. Kerona Rastellum.

K. orbicularis membranacea, nasuta, corniculis in tota pagina. Membranaceous, orbicular kerona, with one projecting point, the upper surface covered with small horns. There are three rows of horns on the back, which nearly occupy the whole of it. It was found in river water.

261. Kerona Lyncaster.

K. subquadrata, rostro obtuso, disco corniculis micantibus. This species of kerona is rather square, and its disc furnished with shining horns. See Zool. Dan. prod. add. p. 281.

262. Kerona Histrio.

K. oblonga, antice punctis mucronatis nigris, postice pinnulis longitudinalibus instructa. Plate XXVII. Fig. 20.

It is an oblong membrane, pellucid, with four or five black points in the fore-part, which are continually changing their situation, thick set with small globules in the middle, among which four larger ones are sometimes perceived, these are probably eggs; in the middle space of the hind-part are some longitudinal strokes resembling bristles, which, however, do not seem to project beyond the body. b, the horns; c, some hairs; d, a solitary horn; e, a large globule; f, some bristles.

263. Kerona Cypris.

K. obovata, versus postica superne sinuata, antice crinita. Plate XXVII. Fig. 21. Egg-shaped, towards the hind-part sinuated, the fore-part hairy.

This animalculum is compressed, and somewhat of a pear-shape; the fore-part broad and blunt; the front is furnished with short hairs or little vibrating points inserted under the edge a, shorter in the hind-part e, partly extended straight, and partly bent down, having a retrograde motion. It is found in water which is covered with lemna.

264. Kerona Haustrum.

K. orbiculata, corniculis mediis, antice membranacea ciliata, postice setosa. Orbicular kerona, with the horns in the middle, the fore-part membranaceous and ciliated, and several bristles at the hinder-part.

265. Kerona Haustellum.

Differs from the preceding only in having the hinder-part without any bristles.

266. Kerona Patella.

K. univalvis, antice emarginata corniculata, postice setis flexilibus pendulis. Plate XXVII. Fig. 22 and 23. Kerona with a univalved shell, orbicular, crystalline; the fore-part somewhat notched; the fleshy body lies in the middle of the shell; above and below are hairs or horns of different lengths jutting out beyond the shell, and acting instead of feet and oars, some of which are bent; the superior ones constitute a double transverse row. a, the fore-part; b, the horns; d, a lunated figure in the shell; c, a pulpous body; f, bristles at the hinder-part.

267. Kerona Vannus.

K. ovalis subdepressa, margine altero flexo, opposito ciliato, corniculis anticis, setisque posticis. Oval and rather flat kerona, with one edge bent, the opposite one ciliated, the front furnished with horns, and the hind-part with bristles.

268. Kerona Pullaster.

K. ovata, antice sinuata, fronte crestata, basi crinita. Plate XXVII. Fig. 24 and 25. Oval, the fore-part sinuated, a crest on the front, the base hairy.

It agrees in many respects with the trichoda pulex, No. 252; but the upper part is pellucid, without any black molecules; the front truncated, the whole surface of the head covered with hair, and the fore-part sinuous. a, the horns; b, the hairs at the hinder-part; c, the cilia of the front.

269. Kerona Mytillus.

K. subclavata, utraque extremitate latiori, hyalina ciliata. Plate XXVII. Fig. 29. Rather clubbed, broad at both extremities, clear and ciliated.

A large animalculum, the fore and hind-part rounded, very pellucid and white, dark in the middle, with black intestines, intermixed with a few pellucid vesicles; both extremities appear as if composed of two thin plates. The fore-part is ciliated, the hairs short, lying within the margin; it is also ornamented with two small horns, erected from an obscure mass; with these it agitates the water, forming a little whirlpool. The hind-part is likewise ciliated, and furnished with two bristles, extending beyond the margin. a, the horns; b, the fore-part ciliated; c, the hind-part; d, projecting bristles.

270. Kerona Lepus.

K. ovata, apice crinito, basi setosa. Egg-shaped, the fore-part hairy, the base furnished with bristles.

The body is egg-shaped, compressed, pellucid, and crowned with short waving hairs, the base terminating with bristles.

271. Kerona Silurus.

K. oblonga, antice et postice crinita, dorso ciliato. Oblong, the fore and hind-part hairy, the back ciliated.

An oval smooth animalculum, somewhat crooked and opake, with a fascicle of vibrating hair on the fore-part; it has a sharp tail, furnished with unequal rows of moveable hairs, producing a rotatory motion; in the inside are some partly lucid, and partly opake points. The figure varies from oval to oblong, the filaments of the conferva are often entangled in the tail.

272. Kerona Calvitium.

R. latiuscula, oblonga, antice corniculis micantibus. Rather broad, oblong, with glittering horns on the fore-part.

The body is rather broad and flat, both sides obtuse, filled with black molecules, and there is a dark spot near the hinder-part, where there are likewise a few short bristles. The interjacent vesicles are pellucid; no hairs on the fore-part, but instead thereof two little moveable horns, and from three to five moveable black points. It is found in the infusions of vegetables.

273. Kerona Pustulata.

K. ovalis convexa, postice altero margine sinuata, utraque extremitate crinita, corniculisque anticis. Oval, convex, kerona, one edge of the hinder-part sinuated, both ends set with hairs, and some horns placed on the fore-part. This animalculum was found in salt water.

XV. HIMANTOPUS.

Vermis inconspicuus, pellucidus, cirratus. A pellucid, invisible, cirrated[127] worm.

274. Himantopus Acarus.

H. ventrosus, postice cirratus, antice acuminatus. Plate XXVII. Fig. 27. Round and prominent himantopus, the hinder-part cirrated, the fore-part sharp.

It is a lively, conical, ventricose animalculum, full of black molecules, the fore-part bright and transparent. The apex, which has long hairs on the under part set like rays, is more or less attenuated, at the will of the little creature; four locks of long and crooked hair, or feet, proceed from the belly; and it is continually moving these and the other hairs in various directions. It is found, though seldom, where the lemna grows. a, the apex; b, the ciliated part; c, the feet.

275. Himantopus Ludio.

H. cirrata, supra crinita, cauda sursum extensa. Plate XXVII. Fig. 26. Curled himantopus, the upper part hairy, the tail extended upwards.

This is a lively and diverting animalculum, smooth, pellucid, full of small points, the fore-part clubbed and a little bent, the hind-part narrow; the base obliquely truncated, and terminating in a tail stretched out transversely. The top of the head, and the middle of the back b, are furnished with long vibrating hairs; three moveable and flexible curls a, are suspended from the side of the head, at a distance from each other. When the animalculum is at rest, its tail is curled; but when in motion, it is drawn tight, and extended upwards, frequently appearing as if it were cleft, as at f.

276. Himantopus Sannio.

H. incurvata, supra ciliata, infra crinita. Crooked himantopus, the upper part ciliated, the under part hairy.

This very much resembles the himantopus ludio, the cilia are longer than the hairs, and are continually vibrating; it has two moveable curls hanging on the side of the head. Is found, though seldom, in water where the lemna grows.

277. Himantopus Volutator.

H. lunatus, antice cirratus. Lunated himantopus, the fore-part hairy.

A very lively animalculum, often turning round in a circular direction. Its shape is that of a crescent, with some crystalline points; the convex part is furnished with a row of hairs, which are longest towards the tail, and underneath are four feet.

278. Himantopus Larva.

H. elongatus, medio cirratus. Long himantopus, cirrated in the middle.

The body is rather depressed and long; the hinder-parts acute, and generally curved, pellucid, and filled with granular molecules. Its motion resembles that of the himantopus ludio, No. 275, but its figure, and the situation of its parts are different.

279. Himantopus Charon.

H. cymbæformis fulcata, in fovea ventrali cirrata. Boat-shaped furrowed himantopus, the hollow part of the belly cirrated.

An oval pellucid membrane, the fore-part hairy, furrowed longitudinally, each side bent up, so as to form an intermediate hollow place, or belly, filled with grey molecules; beneath the middle it has several bent diverging rows of hairs; no hairs on the hinder-part. It is found in sea water, but rarely.

280. Himantopus Corona.

H. semiorbiculata, depressa, in utraque pagina cirrata. Semiorbicular himantopus, flattened, both sides cirrated.

A membranaceous lamina, very thin, pellucid, crystalline, and semilunar; the edge of the base is thick set with molecular intestines; the fore-part furnished with short hairs, or a kind of mane; towards the hind-part are three equal curved hairs, or spines.

XVI. VORTICELLA.

Vermis contractilis, nudus, ciliis rotatoriis. A naked worm, with rotatory cilia, capable of contracting and extending itself.

281. Vorticella Cincta.

V. trapeziformis, nigro-viridis, opaca. Plate XXVII. Fig. 30. This vorticella is in the form of a trapezium, of a blackish green colour, and opake.

It is of an irregular shape, sometimes assuming an oval figure, and appearing as if girt round with a transverse keel, a. It is invisible to the naked eye, ciliated on every side; the hairs all moveable, and longer on one side than the other.

282. Vorticella Sphæroida.

V. cylindrico-globosa, uniformis, opaca. A globous cylinder, uniform and opake.

To the naked eye this appears also little more than a point, but the microscope exhibits it as a globular mass of a dark green colour. It occasions a vehement motion in the surrounding water, which is probably effected by some very short hairs, which are perceptible.

283. Vorticella Viridis.

V. cylindracea, uniformis, viridis opaca. Plate XXVII. Fig. 31. Cylindrical, uniform, green, and opake.

This vorticella is visible to the naked eye, appearing like a minute green point; but the microscope discovers it to be nearly cylindrical, of a dark green colour, a little thicker at the fore-part a, than the hinder-part b, and both extremities obtuse. It appears to be totally destitute of limbs; notwithstanding which, it keeps the water in constant motion; so that it has probably some invisible rotatory instrument. It does not change its figure. Its motion is sometimes circular, at others, in a straight line. At c, some short hairs are visible.

284. Vorticella Lunifera.

V. viridis, postice lunata, medio margine mucronato. Green vorticella, the hinder part lunated, with a point in the middle projecting from the edge.

The fore-part obtuse, the base broad, and hollowed away like a crescent, with a protuberance in the middle of the concave part shorter than the horns or points of the crescent; the fore-part is ciliated. It is found in salt water.

285. Vorticella Bursata.

V. viridis, apertura truncata, papillaque centrali. Plate XXVII. Fig. 32. Green vorticella, the aperture truncated, with a central papillary projection.

Round and prominent, filled with molecules; the fore-part truncated, and both sides of it pellucid; in the center of the aperture there is a prominent papilla or nipple, which when the animalculum is at rest, appears notched; the edge of the aperture is surrounded with cilia; these are sometimes all erect, shining, and in motion, or part bent back and quiescent, and part in motion; sometimes a few of them are collected together, and turned back like little hooks, one on each side. It is found in salt water. a, the cilia; b, the projecting papilla; c, the pellucid space at the fore-part.

286. Vorticella Varia.

V. cylindrica, truncata, opaca, nigricans. Cylindrical, truncated, opake, blackish-coloured vorticella, the fore-part ciliated.

287. Vorticella Sputarium.

V. ventrosa, apertura orbiculari, ciliis longis raris excentricis. Round and prominent, with an orbicular aperture, and long hairs radiating as from a center.

This is one of the most singular of the microscopic animalcula; when viewed sidewise, it is sometimes nearly cylindrical, but somewhat tapering towards the hinder-part, and having a broad pellucid edge; viewed from the top, it has sometimes a broad face or disc furnished with radiating hairs, the under part contracted into a globular shape, of a dark green colour, and filled with small grains. It was found in October with the lesser lemna.

288. Vorticella Nigra.

V. trochiformis nigra. Plate XXVII. Fig. 36 and 37. Top-shaped black vorticella.

This may be seen with the naked eye, appearing like a black point swimming on the surface of the water; the microscope exhibits it as a minute conical body, opake, obtuse, and ventricose at one extremity, and acute at the other. When it extends the extremities, two small white hooks become visible; by the assistance of these it moves in the water, and it is probable from some circumstances that they inclose a rotatory organ. It moves continually in a vacillating manner on the top of the water. It is found in August, in meadows that are covered with water. a, the rotatory organ; b, the two small hooks; c, the acute end.

289. Vorticella Multiformis.

V. viridis, opaca, varia, vesiculis sparsis. Green, opake, variable vorticella, with vesicles scattered about the body.

The vesicles of this vorticella are larger; in other respects it so much resembles the preceding one, that a further description is unnecessary. It is found in salt water.

290. Vorticella Polymorpha.

V. multiformis, viridis, opaca. Plate XXVII. Fig. 33, 34, 35. Many-shaped vorticella, green, opake.

To the naked eye it appears like a green point, moving with great agility; but, when viewed through a microscope, it assumes such a variety of forms, that they can neither be exhibited to the eye by drawings, nor described by words; it is truly one of the wonders of nature, astonishing the mind, fatiguing the eye, and continually exciting the beholder to ask,

The body is granulous, and a series of pellucid points is sometimes to be observed, as at b b.

Fig. 33, 34, 35, represent this vorticella in three different forms; a, the fore-part; g, the hind-part; c, the fore-part simple; d, the fore-part turned in or doubled.

291. Vorticella Cucullus.

V. elongata, teres, apertura oblique truncata. This vorticella is long, round, the aperture or mouth obliquely truncated.

This being visible to the naked eye, may likewise be ranked among the larger vorticellæ. The body is somewhat conical, of a dingy red colour; its shape has been compared to that of a grenadier’s cap.

292. Vorticella Utriculata.

V. Viridis, ventricosa, productilis, antice truncata. Green vorticella, the belly round and prominent, capable of being lengthened or shortened; the fore-part truncated, much in the shape of a common water-bottle; the neck is sometimes very long, at others, very short, and filled with green molecules.

293. Vorticella Ocreata.

V. subcubica, infra in angulum obtusum producta. This vorticella is somewhat of a cubical figure, the under part bent in an obtuse angle.

It is a very singular animalculum, in shape somewhat resembling the lower part of a boot; the apex of the upper part or leg is truncated and ciliated, the heel pointed, and the foot round. It is to be found in rivers, though very rarely.

294. Vorticella Valga.

V. cubica, infra divaricata. Cubical vorticella, the lower part divaricated.

This is as broad as long, and filled with grey molecules, the apex truncated and ciliated; both angles of the base projecting outwards, one somewhat like a wart, the other like a finger. It is found in marshy waters.

295. Vorticella Papillaris.

V. ventricosa, antice truncata, papilla caudali et laterali hyalina. Big-belled vorticella, the fore-part truncated, with a papillary tail, and a splendid papillary excrescence on the side. It is found in marshes where the conferva nitida grows.

296. Vorticella Sacculus.

V. cylindracea, apertura repanda, margine reflexo. Cylindrical vorticella, the aperture broad and flat, the edge turned down.

A thick animalculum, of an equal diameter everywhere, and filled with molecules; the edge of the mouth is bent back, the hinder-part obtuse, sometimes notched and contracted, with cilia on both sides of the mouth.

297. Vorticella Cirrata.

V. ventrosa, apertura sinuata, cirro utrinque ventrali. Big-bellied vorticella, the aperture sinuated, two tufts of hair on each side of the belly. It is found in ditch water.

298. Vorticella Nasuta.

V. cylindracea, crateris medio mucrone prominente. Plate XXVII. Fig. 38, 39. Cylindrical, with a prominent point in the middle of the cup.

An animalculum that is invisible to the naked eye; but the microscope discovers it to be furnished with a rotatory organ, which encompasses the middle of the body.

It is pellucid, cylindrical, of an unequal size; the fore-part, a, truncated and ciliated, and a triangular prominence, e, in the middle of the aperture; the hind-part is obtuse, with a point on each side of the middle of the body. This is the appearance of the little creature when in motion; but when the water is nearly exhaled, some further parts of its structure are rendered visible; two rotatory organs are now observable; one on the fore-part, and the other encompassing the middle of the body, h h; the hairs of the latter are in vehement motion. Other fascicles of moving hair may likewise be observed, and the variegated and quick motion of this apparatus is very surprizing, especially if the animalculum be big with young, moving at the same time within the mother.