Legion III. NASSELLARIA, (continued 12)

Dimensions.—Length of the three joints, a 0.04, b 0.07, c 0.04; breadth, a 0.03, b 0.07, c 0.05.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

6. Lithornithium hirundo, Ehrenberg.

Lithocampe hirundo, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 65.

Lithornithium hirundo, Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 53.

Shell nearly ovate, with two deep strictures. Length of the three joints = 2 : 6 : 4, breadth = 2 : 7 : 5. Cephalis hemispherical, with an oblique, conical horn of twice the length. Thorax hemispherical, with three long, angular, little divergent wings of twice the length, which are S-shaped, curved, and arise from its lower third, immediately above the girdle. Abdomen inversely conical. Pores irregular, roundish, of different sizes. In the figure of Ehrenberg the abdomen is broken off; in a specimen from Caltanisetta, with somewhat shorter and broader wings, I found it complete.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.04; breadth, a 0.02, b 0.07, c 0.05.

Habitat.—Fossil in Tertiary rocks of the Mediterranean (Ægina, Greece; Caltanisetta, Sicily).

Genus 596. Sethornithium,^[213] Haeckel, 1881, Prodromus, p. 436.

Definition.—Theoperida (vel Tricyrtida triradiata clausa) with three latticed lateral wings on the thorax.

The genus Sethornithium differs from the preceding Lithornithium, its ancestral form, only in the fenestration of the three thoracic wings, and bears therefore to it the same relation that Dictyoceras exhibits to Pterocorys.

1. Sethornithium dictyopterum, n. sp. Pl. 68, fig. 14.

Shell ovate, with two slight strictures. Length of the three joints = 2 : 4 : 3, breadth = 1 : 5 : 4. Cephalis ovate, with a pyramidal horn of twice the length. From the middle part of the thorax arise three broad, triangular, latticed wings of about the same length, the distal end of each of which is curved downwards. Abdomen inversely conical. Pores regular, circular. (Similar to Lithornithium fringilla, Pl. 67, fig. 2, but with much larger wings, which in the greater part are fenestrated.)

Dimensions.—Length of the three joints, a 0.04, b 0.08, c 0.06; breadth, a 0.02, b 0.1, c 0.08.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Genus 597. Theopera,^[214] Haeckel, 1881, Prodromus, p. 436.

Definition.—Theoperida (vel Tricyrtida triradiata clausa) with three lateral wings, beginning from the sides of the thorax and prolonged into the sides of the abdomen.

The genus Theopera differs from the two preceding genera in the greater extension of the three lateral wings, which are prolonged from their original base, the thorax, into the inversely conical abdomen. It has therefore an intermediate position between the preceding and the following genera. It differs from the similar Pterocanium and Theopodium in the closure of the constricted and fenestrated mouth.

1. Theopera prismatica, n. sp. (Pl. 67, fig. 7).

Rhopalocanium prismaticum, Haeckel, 1879, Atlas, pl. lxvii. fig. 7.

Shell three-sided prismatic, with three broad and long hyaline wings, which are prolonged from the collar stricture almost to the basal end, with three parallel edges. Length of the three joints = 2 : 8 : 10, breadth = 3 : 9 : 8. Cephalis hemispherical, with a conical horn of the same length. Thorax subspherical; abdomen inversely ovate; pores of both small, regular, circular, of equal size.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.1; breadth, a 0.03, b 0.09, c 0.08.

Habitat.—South Atlantic, Station 332. depth 2200 fathoms.

2. Theopera pyramis, Haeckel.

Rhopalocanium sp., Bury, 1862, Polycystins of Barbados, pl. xvii. fig. 8.

Shell three-sided pyramidal, with three broad and long hyaline wings, which are prolonged from the collar stricture almost to the basal end, with three diverging edges. Length of the three joints = 3 : 8 : 11, breadth = 4 : 8 : 9. Cephalis subspherical, with a conical horn of the same length. Thorax hemispherical; abdomen inversely campanulate. Pores in the abdomen twice to three times as broad as in the thorax, subregular, circular. Differs from the preceding species mainly in the broader pyramidal form and the divergence of the wings.

Dimensions.—Length of the three joints, a 0.03, b 0.08, c 0.11; breadth, a 0.04, b 0.08, c 0.09.

Habitat.—Fossil in Barbados.

3. Theopera fusiformis (Pl. 67, fig. 5).

Shell nearly spindle-shaped, rough, with two slight strictures. Length of the three joints = 2 : 3 : 6, breadth = 2 : 5 : 4. Cephalis hemispherical, large, with an oblique conical horn of the same length. Thorax hemispherical; abdomen inversely conical. Pores irregular, roundish, of very different sizes. Three wings short, broad, diverging, triangular, and striated, embracing at the base the lumbar stricture, the lower third of the thorax and the upper third of the abdomen.

Dimensions.—Length of the three joints, a 0.04, b 0.06, c 0.12; breadth, a 0.045, b 0.1, c 0.08.

Habitat.—Central Pacific, Stations 263 to 274, depth 2350 to 2925 fathoms.

4. Theopera luscinia, Haeckel.

Lithornithium luscinia, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 78, Taf. iv. fig. 9.

Shell slenderly ovate, with distinct collar, but indistinct lumbar strictures. Length of the three joints = 1 : 3 : 6, breadth = 1 : 5 : 5. Cephalis hemispherical, with a slender cylindrical horn of three times the length, bearing a spindle-shaped spinulate top (like a fir-cone). Pores subregular, circular, twice as broad in the abdomen as in the thorax. Three wings arising with broad triangular base, embracing the lower third of the thorax and the upper third of the abdomen, prolonged into three slender diverging spines, as long as the shell.

Dimensions.—Length of the three joints a 0.015, b 0.05, c 0.1; breadth, a 0.02, b 0.07, c 0.07.

Habitat.—Fossil in Barbados.

5. Theopera chytropus, n. sp. (Pl. 67, fig. 6).

Shell slender, ovate, with distinct collar, but indistinct lumbar stricture. Length of the three joints = 1 : 2 : 5, breadth = 1 : 3 : 3. Cephalis hemispherical, with a conical horn of the same length. Pores in the thorax and abdomen of similar shape, irregular, roundish. Three wings with broad triangular base attached at the upper half of the shell, in the lower half free, diverging, with a spinulate knob at the distal end.

Dimensions.—Length of the three joints, a 0.025, b 0.06, c 0.15; breadth, a 0.03, b 0.09, c 0.09.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms.

6. Theopera cortina, n. sp. (Pl. 67, fig. 8).

Shell slender, ovate, with distinct collar, but indistinct lumbar stricture. Length of the three joints = 1 : 2 : 6, breadth 1 : 4 : 4. Cephalis subspherical, with an elegant pyramidal horn of three times the length, bearing an ovate, spinulate knob. Pores subregular, circular, two or three times as large in the abdomen as in the thorax. The three wings are slightly elevated small ribs on the thorax, arise with broad, triangular, striated bases in the upper half of the abdomen, and are prolonged into three slender diverging feet, which are as long as the shell, and bear a spinulate, ovate knob at the distal end.

Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.13; breadth, a 0.03, b 0.08, c 0.08.

Habitat.—Tropical Atlantic, Station 338, depth 1990 fathoms.

Genus 598. Rhopalocanium,^[215] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

Definition.—Theoperida (vel Tricyrtida triradiata clausa) with three lateral wings on the sides of the inversely conical abdomen, which bears no vertical terminal horn on the basal apex.

The genus Rhopalocanium, and the closely allied Rhopalatractus which follows, differ from the preceding Theopera, their probable ancestral form, in the origin of the three lateral wings from the inversely conical abdomen, the thorax bearing no wings. The upper part of the wing bases, which arose formerly from the thorax, is here reduced and lost.

1. Rhopalocanium lasanum, n. sp. (Pl. 67, fig. 10).

Shell subovate, with two distinct strictures. Length of the three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with a conical, dimpled horn of twice the length. Thorax subconical, abdomen campanulate, both with irregular, circular pores. Three wings cylindrical, divergent, about as long as the shell, striated, with an ovate, dimpled knob at the distal end, their broad triangular base being attached to the upper half of the abdomen. (Form rather variable.)

Dimensions.—Length of the three joints, a 0.02, b 0.07, c 0.09; breadth, a 0.03, b 0.09, c 0.12.

Habitat.—Central Pacific, Stations 263 to 268, depth 2650 to 3000 fathoms.

2. Rhopalocanium ornatum, Ehrenberg.

Rhopalocanium ornatum, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 9; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xvii. fig. 8.

Shell nearly spindle-shaped, with two distinct strictures. Length of the three joints = 1 : 3 : 6, breadth = 1 : 4 : 3. Cephalis hemispherical, with a stout, cylindrical horn of twice the length, bearing a dimpled cone. Thorax ovate, campanulate. Abdomen inversely conical. Pores subregular, circular, twice as large in the thorax as in the abdomen. Three wings compressed, slender, divergent, slightly longer than the abdomen, bearing an ovate, dimpled cone at their distal end, with the broad, triangular, striated base attached to the upper third of the abdomen.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.12; breadth, a 0.025, b 0.08, c 0.07.

Habitat.—Fossil in Barbados.

3. Rhopalocanium cortinium, n. sp.

Shell slender, ovate, nearly of the same form as, and with similar fenestration to that of Theopera cortina, (Pl. 67, fig. 8). It differs from the latter mainly by the absence of the three thoracic ribs, characteristic of Theopera. Length of the three joints = 1 : 2 : 6, breadth = 1 : 4 : 4. The three wings arise by a broad, triangular, striated base from the upper half of the abdomen, below the lumbar stricture. The cephalic horn and the three divergent wings are shorter, and at the distal end not so much thickened as in Theopera cortina.

Dimensions.—Length of the three joints, a 0.025, b 0.045, c 0.12; breadth, a 0.03, b 0.07, c 0.08.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

4. Rhopalocanium pythia, n. sp.

Rhopalocanium ornatum, Bury, 1862, Polycystins of Barbados, pl. vi. fig. 1.

Shell nearly ovate, with two deep strictures. Length of the three joints = 1 : 4 : 8, breadth = 1 : 4 : 4. Cephalis subspherical, with a conical horn of three times the length. Thorax inflated, abdomen inversely campanulate and prolonged into a short, conical, latticed tube. Pores subregular, circular. Three wings slender, as long as the abdomen, arising by a broader base from the uppermost part of the abdomen, their thickened end being curved inwards.

Dimensions.—Length of the three joints, a 0.02, b 0.07, c 0.15; breadth, a 0.03, b 0.08, c 0.07.

Habitat.—Fossil in Barbados.

5. Rhopalocanium delphicum, n. sp. (Pl. 67, fig. 9).

Shell nearly spindle-shaped, with two deep strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 3. Cephalis hemispherical, with a slender, conical, curved horn, as long as the hemispherical thorax. Abdomen inversely campanulate, prolonged into a short, conical, latticed tube. Pores subregular, circular. Three wings arising by a narrow base from the uppermost part of the abdomen, slender, cylindrical, S-shaped, curved, divergent, with a thick scaly appendix like a fir-cone at the distal end.

Dimensions.—Length of the three joints, a 0.025, b 0.07, c 0.14; breadth, a 0.03, b 0.09, c 0.08.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

Genus 599. Rhopalatractus,^[216] Haeckel, 1881, Prodromus, p. 437.

Definition.—Theoperida (vel Tricyrtida triradiata clausa) with three lateral wings on the sides of the inversely conical abdomen, which bears a vertical terminal horn on the basal apex.

The genus Rhopalatractus, one of the most remarkable forms of Tricyrtida, differs from the preceding Rhopalocanium, its ancestral form, in the production of a vertical, basal horn, which descends from the basal apex of the inversely conical abdomen, and is opposed to the upper apical horn of the cephalis. The shell becomes here, therefore, exquisitely spindle-shaped.

1. Rhopalatractus pentacanthus, n. sp. (Pl. 68, fig. 11).

Shell very thick-walled, with two sharp strictures. Length of the three joints = 1 : 6 : 8, breadth = 1 : 6 : 7. Cephalis hemispherical, with conical cavity, and a conical horn of twice the length. Thorax subspherical, separated from the abdomen by a deep lumbar stricture, with small, regular, circular, hexagonally-framed pores. Abdomen three-sided prismatic, with three strong, prominent, wing-shaped edges, which are slightly divergent towards the base, and prolonged into three pyramidal feet about as long as the thorax. Pores of the abdomen disposed in longitudinal rows, which are separated by denticulate crests. Abdominal base inversely pyramidal, and prolonged into a very large, cylindrical, basal, axial spine, nearly as long as the whole shell.

Dimensions.—Length of the three joints, a 0.02, b 0.12, c 0.15; breadth, a 0.03, b 0.11, c 0.14.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

2. Rhopalatractus foveolatus, n. sp. (Pl. 68, fig. 10).

Shell slenderly ovate, thick-walled, with rough, dimpled surface. Length of the three joints = 1 : 3 : 5, breadth = 2 : 4 : 4. Cephalis hemispherical, with spherical cavity, and a thick, conical spine of the same length. Thorax subspherical, with subregular, circular pores. Abdomen inversely conical, with larger, irregular, roundish pores, prolonged at the distal end into a cylindrical, axial, basal spine of about half its length. From the middle part of the abdomen arise three lateral, conical feet, which are slightly curved and divergent downwardly, scarcely as long as the basal spine. All five spines are dimpled.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.1; breadth a 0.04, b 0.08, c 0.08.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

3. Rhopalatractus fusiformis, n. sp.

Shell slender, spindle-shaped, nearly of the same form as in the preceding species. Length of the three joints = 1 : 2 : 6, breadth = 1 : 2 : 2. Cephalis subspherical, with a cylindrical horn three times the length. Pores subregular, circular, of equal breadth in the thorax and in the abdomen, which is prolonged into a cylindrical, axial, basal spine of the same length. From the upper third of the abdomen arise, from a broad triangular base, three conical wings of half the length, divergent and slightly curved inwards.

Dimensions.—Length of the three joints, a 0.025, b 0.05, c 0.15; breadth, a 0.03, b 0.06, c 0.06.

Habitat.—Central Pacific, Station 263, depth 2650 fathoms.

4. Rhopalatractus fenestratus, n. sp. (Pl. 68, fig. 12).

Dictyatractus fenestratus, Haeckel, 1881, Prodromus et Atlas.

Shell nearly spindle-shaped, with two distinct strictures. Length of the three joints = 1 : 3 : 6, breadth = 1 : 4 : 4. Cephalis hemispherical, with a large, club-shaped horn, nearly as long as the abdomen, sulcated by longitudinal ribs, which are elegantly denticulate in the distal half. Thorax subspherical. Abdomen subovate, prolonged into a pyramidal, axial, basal spine, half as long as the thorax. Pores subregular, circular. From the upper half of the abdomen arise three stout, lateral, diverged wings of about the same length, which are curved inwards and fenestrated both at the broad triangular base and at the thickened, three-edged distal end.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.12; breadth, a 0.03, b 0.08, c 0.08.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

Genus 600. Lithochytris,^[217] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

Definition.—Theoperida (vel Tricyrtida triradiata clausa) with a three-sided pyramidal abdomen, the triangular base of which is prolonged at the three corners into three terminal feet.

The genus Lithochytris differs from all the other Theoperida in the absence of lateral wings and the possession of three divergent, terminal feet, which arise from the three corners of the three-sided pyramidal abdomen. It repeats, therefore, among the Tricyrtida, that characteristic formation which Sethochytris and Tetrahedrina represent among the Dicyrtida. Some species may be derived from Pterocanium, other species from Podocyrtis, by the development of a lattice-plate closing the terminal mouth.

Subgenus 1. Lithochytrodes, Haeckel.

Three feet of the abdomen solid, not fenestrated, representing external apophyses of the triangular shell-base.

1. Lithochytris cortina, n. sp. (Pl. 67, fig. 12).

Shell three-sided pyramidal, without external strictures, but with two internal girdles. Length of the three joints = 2 : 2 : 5, breadth = 3 : 4 : 6. Cephalis large, truncate-pyramidal, with nine deep divergent ribs (and nine longitudinal rows of pores between them), and with a stout pyramidal horn of half the length. The three prominent edges of the thorax and abdomen are prolonged over the base of the pyramid into three very stout, solid, subovate feet, about as long as the thorax.

Dimensions.—Length of the three joints, a 0.04, b 0.04, c 0.1; breadth, a 0.06, b 0.08, a 0.12.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

2. Lithochytris pyriformis, n. sp. (Pl. 67, fig. 13).

Shell pyramidal, nearly pear-shaped, with two distinct strictures. Length of the three joints = 1 : 1 : 3, breadth = 1 : 2 : 3. Cephalis large, pear-shaped, with a short pyramidal horn of half the length. Thorax and abdomen rounded, without prominent edges. Three basal feet pyramidal, solid, nearly vertical, as long as the thorax. Pores irregular, roundish, in the abdomen large, twice to three times as broad as in the thorax.

Dimensions.—Length of the three joints, a 0.03, b 0.03, c 0.08; breadth, a 0.04, b 0.06, c 0.09.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

3. Lithochytris tripodium, Ehrenberg.

Lithochytris tripodium, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 76, Taf. iv. fig. 11.

Shell pyramidal, nearly pear-shaped, with two distinct strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 2 : 5. Cephalis with a horn of the same length, conical. Thorax and abdomen rounded, without prominent edges. Three basal feet conical, solid, strongly divergent, shorter than the thorax. Pores subregular, circular, twice as broad in the abdomen as in the thorax.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.03, b 0.05, c 0.1.

Habitat.—Fossil in Barbados.

Subgenus 2. Lithochytridium, Haeckel.

Definition.—Three feet of the abdomen hollow and fenestrated, representing direct protuberances or corner prolongations of the triangular shell-base.

4. Lithochytris galeata, n. sp. (Pl. 67, fig. 16).

Shell pyramidal, with two sharp strictures. Length of the three joints = 1 : 1 : 4, breadth = 1 : 2 : 4. Cephalis subspherical, with an oblique pyramidal horn of the same length. Thorax somewhat larger. Abdomen inflated, with three sharp, prominent edges, which are prolonged over the shell-base into three pyramidal, hollow, and fenestrated feet, longer than the thorax. Pores subregular, circular, twice as broad in the abdomen as in the thorax.

Dimensions.—Length of the three joints, a 0.025, b 0.025, c 0.1; breadth, a 0.025, b 0.05, c 0.1.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

5. Lithochytris pileata, Ehrenberg.

Lithochytris pileata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 76, Taf. v. fig. 3.

Shell three-sided pyramidal, with deep collar, but indistinct lumbar stricture. Length of the three joints = 2 : 2 : 9, breadth = 3 : 5 : 10. Cephalis with a conical horn of the same length, pear-shaped. Thorax very short and broad. Abdomen inflated, with three sharp, prominent edges, which are prolonged over the shell-base into three pyramidal, hollow and fenestrated feet, the lower edge of which is horizontal. Pores regular, circular, of equal size in the thorax and abdomen.

Dimensions.—Length of the three joints, a 0.02, b 0.02, c 0.09; breadth, a 0.03, b 0.05, c 0.1.

Habitat.—Fossil in Barbados.

6. Lithochytris lucerna, n. sp. (Pl. 67, fig. 14).

Shell three-sided pyramidal, with two indistinct strictures. Length of the three joints = 1 : 2 : 5, breadth = 2 : 3 : 8. Cephalis small, with a horn of the same length, conical. Thorax with subspherical cavity. Abdomen with three rounded, prominent edges, which are prolonged over the shell-base into three conical, hollow, and fenestrated feet, twice as long as the thorax, with a thick, pyramidal, terminal spine. Pores subregular, circular, of equal size in the thorax and abdomen.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.1; breadth, a 0.04, b 0.06, c 0.16.

Habitat.—South Pacific, Station 297, depth 1775 fathoms.

7. Lithochytris lanterna, n. sp. (Pl. 67, fig. 11).

Shell three-sided pyramidal, with two distinct strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 6. Cephalis small, with a pyramidal slender horn of twice the length. Thorax with subspherical cavity. Abdomen with three sharp prominent edges, which are prolonged over the convex shell-base into three slender, prismatic, hollow, fenestrated feet, strongly divergent, twice as long as the thorax (seen in fig. 11 from the vaulted base). Pores circular, twice as broad in the abdomen as in the thorax.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.02, b 0.06, c 0.12.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

8. Lithochytris pyramidalis, Ehrenberg.

Lithochytris pyramidalis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 76, Taf. v. fig. 1.

Shell three-sided pyramidal, without external strictures, but with two internal transverse girdles. Length of the three joints = 1 : 2 : 6, breadth = 2 : 4 : 8. Cephalis with a short horn of half the length, conical. Cavity of the thorax subspherical. Abdomen with three rounded edges, prolonged over the concave base into three pyramidal, hollow, and fenestrated feet, twice as long as the thorax. Pores large, irregular, roundish.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.12; breadth, a 0.04, b 0.08, c 0.16.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms; fossil in Barbados.

9. Lithochytris pteropus, n. sp. (Pl. 67, fig. 15).

Shell three-sided pyramidal, with two indistinct strictures, but with two broad, internal girdles. Length of the three joints = 2 : 2 : 6, breadth = 2 : 3 : 9. Cephalis with a small horn of half the length, pear-shaped. Thorax broader than long. Abdomen with three prominent, rounded edges, prolonged over the concave base into three conical, hollow, and fenestrated feet, twice as long as the thorax. Pores small, circular, irregular, in longitudinal series along the edges.

Dimensions.—Length of the three joints, a 0.04, b 0.04, c 0.12; breadth, a 0.04, b 0.06, c 0.18.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

10. Lithochytris vespertilio, Ehrenberg.

Lithochytris vespertilio, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 76, Taf. iv. fig. 10.

Shell three-sided pyramidal, with two indistinct strictures. Length of the three joints = 1 : 2 : 5, breadth = 2 : 3 : 10. Cephalis with a short horn of half the length, conical. Thorax inflated. Abdomen without prominent edges, divided in the lower half into three large, conical, hollow, and fenestrated feet, twice as long as the thorax. Pores small, irregular, roundish.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.1; breadth, a 0.04, b 0.06, c 0.2.

Habitat.—Fossil in Barbados.

Family LXVI. Phormocyrtida, n. fam.

Definition.—Tricyrtida multiradiata. (Cyrtoidea with a three-jointed shell, divided by two transverse constrictions into cephalis, thorax, and abdomen, with numerous, four to nine or more, radial apophyses.)

The family Phormocyrtida, composed of the Theophormida and Theophænida of my Prodromus, comprises those Cyrtoidea in which the lattice-shell is three-jointed, and bears numerous radial appendages (usually six or nine, sometimes more, rarely less, four or five). The two subfamilies differ in the shape of the terminal mouth, which is in the Theophormida a simple wide opening, in the Theophænida closed by a lattice-plate. The phylogenetic origin of the Phormocyrtida may be found either in the Podocyrtida or in the Anthocyrtida; they may be derived either from the former by interpolation of interradial, secondary apophyses between the three primary perradial apophyses; or from the latter by development of an abdomen.

The radial apophyses are originally radial ribs, which arise from the base of the cephalis on the collar stricture, run along the thorax and abdomen, and are often prolonged into terminal feet. Whilst in some forms the radial ribs are completely preserved in both joints, they are in other forms only partly visible (in the abdomen), and very often only their free terminal prolongations are preserved in the form of a corona of feet around the mouth of the thorax. This corona is either simple or double. Sometimes also a corona is developed on the lumbar stricture, between the thorax and abdomen.

These apophyses exhibit a remarkable variety in the great subfamily Theophormida, with open mouth. In the small subfamily Theophænida, however, the apophyses appear as six or nine simple lateral wings on the abdomen.

The Theophormida are richly represented not only in the present seas, but also as fossils in Barbados, and numerous remarkable forms have been already described by Ehrenberg, in his genera Calocyclas and Cycladophora. Many Phormocyrtida belong to the most elegant and admirable forms of Radiolaria.

Synopsis of the Genera of Phormocyrtida.

I. Subfamily Theophormida. Terminal mouth of the abdomen a simple wide opening. Radial ribs enclosed in the wall of the shell, either the thorax or the abdomen. Radial ribs in the thorax and the abdomen. Abdomen flat, dilated, with a wide open mouth, 601. Theophormis.

Abdomen ovate or cylindrical, with constricted mouth, 602. Phormocyrtis

Radial ribs in the abdomen only. Peristome with free terminal feet, 603. Alacorys.

Peristome smooth, without free feet, 604. Cycladophora.

No radial ribs in the shell wall. Peristome with a corona of terminal feet. Terminal corona simple. Abdomen cylindrical or ovate, not dilated, 605. Calocyclas.

Abdomen dilated, truncate, conical or discoidal, 606. Clathrocyclas.

Corona of feet double. Both coronas terminal, 607. Lamprocyclas.

One corona, terminal, the other lumbar, 608. Diplocyclas.

II. Subfamily Theophænida. Terminal mouth of the abdomen closed by a lattice-plate. Six lateral wings, 609. Hexalatractus.

Nine Lateral wings, 610. Theophæna.

I. Subfamily Theophormida. Terminal mouth of the abdomen a simple wide opening.

Radial ribs enclosed in the wall of the shell, either the thorax or the abdomen.

Radial ribs in the thorax and the abdomen.

Abdomen flat, dilated, with a wide open mouth,

601. Theophormis.

Abdomen ovate or cylindrical, with constricted mouth,

602. Phormocyrtis

Radial ribs in the abdomen only.

Peristome with free terminal feet,

603. Alacorys.

Peristome smooth, without free feet,

604. Cycladophora.

No radial ribs in the shell wall. Peristome with a corona of terminal feet.

Terminal corona simple.

Abdomen cylindrical or ovate, not dilated,

605. Calocyclas.

Abdomen dilated, truncate, conical or discoidal,

606. Clathrocyclas.

Corona of feet double.

Both coronas terminal,

607. Lamprocyclas.

One corona, terminal, the other lumbar,

608. Diplocyclas.

II. Subfamily Theophænida.

Terminal mouth of the abdomen closed by a lattice-plate.

Six lateral wings,

609. Hexalatractus.

Nine Lateral wings,

610. Theophæna.

Subfamily 1. Theophormida, Haeckel, 1881, Prodromus, p. 436.

Definition.—Phormocyrtida with the basal mouth of the shell open (vel Tricyrtida multiradiata aperta).

Genus 601. Theophormis,^[218] Haeckel, 1881, Prodromus, p. 436.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with numerous radial ribs enclosed in the wall of the thorax and of the flat dilated abdomen; mouth of the latter wide open.

The genus Theophormis commences the series of the Theophormida, or the multiradiate Podocyrtida, as their oldest and simplest form. The three-jointed shell is flat, campanulate or hat-shaped, and pierced by four or more radial ribs, four of which are primary or perradial, the others secondary or interradial. Theophormis may be derived from the similar Sethophormis by development of a lumbar constriction, and a third joint or abdomen.

1. Theophormis callipilium, n. sp. (Pl. 70, figs. 1-3).

Shell flat, hat-shaped, with two sharp annular strictures. Cephalis large, flatly cap-shaped, with small, irregular, square meshes (fig. 3). The collar septum (fig. 2) is composed (as in the following species) of four crossed, thin, horizontal beams, each of which is inserted at the collar stricture by a three forked branch. From the centre of the collar stricture (in the common nodal point of the four beams) there arises a vertical, axial rod, which is inserted at the flat top of the cephalis by five branches (one central and four lateral). Length of the three joints = 1 : 3 : 2, breadth = 2 : 6 : 11. Thorax flat, campanulate, with four primary perradial ribs (prolongations of the four cortinar beams), and numerous (twenty to thirty) interpolated secondary ribs; four of these are in interradial (midway between the four primary ribs), and bisect the four large, semicircular, perradial meshes at the base of the thorax. Network of the thorax and abdomen subregular, with hexagonal meshes and thin bars. Abdomen flatly expanded, somewhat curved, like the brim of a hat, half as broad in the anterior (frontal) part as in the posterior (occipital) part, which is about as broad as the radius of the thorax. The twenty to thirty radial ribs of the abdomen are prolongations of the thoracic ribs, and are somewhat prominent at the margin of the peristome, which appears therefore elegantly indented.

Dimensions.—Length of the three joints, a 0.02 to 0.03, b 0.06 to 0.08, c 0.03 to 0.06; breadth, a 0.05 to 0.08, b 0.2 to 0.3, c 0.4 to 0.5.

Habitat.—Central Pacific, Station 271, surface.

2. Theophormis medusa, n. sp.

Shell flatly campanulate, with two distinct, annular strictures. Length of the three joints = 1 : 2 : 1, breadth = 2 : 5 : 8. Cephalis large, hemispherical. Thorax flatly conical, with four crossed ribs, opposite in pairs in two meridional planes, perpendicular one to another, and prolonged into the flat, nearly discoidal abdomen, which is half as broad as the thorax. The wall of the abdomen is pierced by eight radial ribs; four secondary ribs being interpolated between the four primary. Network of the entire shell very delicate, with regular, hexagonal meshes, and very thin bars. Peristome circular, not dentate.

Dimensions.—Length of the three joints, a 0.03, b 0.07, c 0.04; breadth, a 0.06, b 0.16, c 0.24.

Habitat.—Central Pacific, Station 266, surface.

3. Theophormis cruciata, n. sp.

Shell flat, campanulate, with two distinct annular strictures. Cephalis flat, cap-shaped, with irregular, square meshes. Thorax flat, conical, with hexagonal meshes. Abdomen flatly expanded, of half the breadth, with larger hexagonal meshes. Thorax and abdomen pierced by four stout radial ribs, lying opposite in pairs in two diameters, perpendicular one to another. No secondary or interradial ribs are interpolated between the four primary. Mouth truncate, circular.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.04; breadth, a 0.05, b 0.18, c 0.25.

Habitat.—Central Pacific, Station 274, surface.

4. Theophormis senaria, n. sp.

Shell flat, hat-shaped, similar to Theophormis callipilium (Pl. 70, figs. 1-3), but with a different number and arrangement of the piercing radial ribs. The cephalis and its collar septum exhibit the same formation as in Sethophormis hexalactis, described above (p. 1245, Pl. 56, fig. 6.) The caudal and sternal ribs, which are opposed in the sagittal plane, are simple, whilst the two lateral ribs are forked. In the flat abdomen there are six secondary or interradial ribs, interpolated between the six primary or perradial ribs of the thorax. Delicate network with regular, hexagonal meshes.

Dimensions.—Length of the three joints, a 0.035, b 0.075, c 0.025; breadth, a 0.07, b 0.2, c 0.3.

Habitat.—Central Pacific, Station 272, surface.

Genus 602. Phormocyrtis,^[219] n. gen.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with numerous radial ribs enclosed in the wall of the thorax, and of the ovate or cylindrical abdomen; mouth of the latter constricted.

The genus Phormocyrtis differs from the preceding Theophormis in the ovate or cylindrical form of the abdomen, the mouth of which is more or less constricted. The former exhibits, therefore, the same relation to the latter that Sethamphora bears to Sethophormis among the Dicyrtida. Phormocyrtis may be derived directly either from Sethamphora by development of an abdomen, or from Pterocorys or Theopilium by multiplication of the three radial ribs.

1. Phormocyrtis carinata, n. sp.

Shell ovate, with two slight strictures. Length of the three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with a stout pyramidal horn of twice the length, and few very small pores. Pores in the campanulate thorax and the inflated abdomen regular, circular, small, and numerous. Six stout prominent ribs, beginning from the collar stricture, arise along the thorax and abdomen, and reach the constricted mouth, which is half as broad as the abdomen. (This species is very similar to Pterocorys carinata, from which it differs in the six complete radial ribs of the shell-wall.)

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.09; breadth, a 0.03, b 0.09, c 0.12.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

2. Phormocyrtis fastosa, Haeckel.

Eucyrtidium fastosum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 291, Taf. ix. fig. 19.

Shell ovate, with two distinct strictures. Length of the three joints = 1 : 3 : 3, breadth = 1 : 5 : 6. Cephalis ovate, with a stout pyramidal horn of the same length, and numerous rather large pores. Pores in the campanulate thorax and the inflated abdomen much smaller, very numerous, regular, hexagonal. Along these two joints arise nine delicate, divergent ribs; these extend almost to the wide mouth, which is slightly constricted.

Dimensions.—Length of the three joints, a 0.03, b 0.09, c 0.08; breadth, a 0.02, b 0.1, c 0.12.

Habitat.—Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen.

3. Phormocyrtis costata, n. sp. (Pl. 69, fig. 6).

Shell smooth, with sharp collar, but indistinct lumbar stricture. Length of the three joints = 2 : 5 : 5, breadth = 2 : 6 : 6. Cephalis conical, with a stout pyramidal horn of twice the length. Thorax and abdomen together nearly cylindrical, constricted towards both poles, with thirty to forty longitudinal ribs, which are nearly parallel, vertical in the middle part, and convergent towards both poles; alternate with the same number of longitudinal rows of regular, circular pores. Mouth with a broad, hyaline, only slightly constricted peristome.

Dimensions.—Length of the three joints, a 0.04, b 0.1, c 0.1; breadth, a 0.04, b 0.12, c 0.12.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

4. Phormocyrtis embolum, Haeckel.

Eucyrtidium embolum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. x. fig. 5.

Shell smooth, with sharp collar, but indistinct lumbar stricture. Length of the three joints = 3 : 7 : 10, breadth = 3 : 9 : 7. Cephalis subspherical, with a pyramidal horn of the same length. Thorax campanulate; abdomen inversely truncate, conical; both with sixteen to twenty longitudinal ribs, and alternate longitudinal rows of small circular pores, converging towards the two poles. Mouth truncate, with broad hyaline peristome.

Dimensions.—Length of the three joints, a 0.03, b 0.07, c 0.1; breadth, a 0.03, b 0.09, c 0.07.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms; fossil in Barbados.

5. Phormocyrtis quadrata, n. sp.

Shell ovate, papillate, with two slight strictures. Length of the three joints = 2 : 3 : 13, breadth = 4 : 6 : 11. Cephalis hemispherical, small, with two divergent, pyramidal horns of twice the length. Along the hemispherical thorax and the ovate inflated abdomen run twenty-four to thirty curved ribs, converging towards the two poles, and alternate with the same number of longitudinal rows of circular, regular pores, disposed in ten to twelve transverse rows. Each pore with a square, elevated frame. Mouth constricted, only one-third as broad as the thorax.

Dimensions.—Length of the three joints, a 0.02, b 0.03, c 0.13; breadth, a 0.04, b 0.06, c 0.11.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

6. Phormocyrtis longicornis, n. sp. (Pl. 69, fig. 15).

Theocorys longicornis, Haeckel, 1881, Prodromus et Atlas, loc. cit.

Shell slender, ovate, rough, with two slight strictures. Length of the three joints = 3 : 8 : 12, breadth = 4 : 10 : 11. Cephalis hemispherical, with a very large, cylindrical horn, about as long as the shell. Thorax hemispherical, with regular, circular, hexagonally-framed pores. Abdomen subcylindrical, with twenty to twenty-four nearly parallel undulate ribs, and alternate longitudinal rows of regular, circular pores. Mouth constricted, circular, about half as broad as the thorax.

Dimensions.—Length of the three joints, a 0.03, b 0.08, c 0.12; breadth, a 0.04, b 0.1, c 0.11.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.

Genus 603. Alacorys,^[220] Haeckel, 1881, Prodromus, p. 436.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with numerous radial ribs in the abdomen, which are prolonged over the mouth into free feet.

The genus Alacorys and the following Cycladophora differ from the preceding two genera in the formation of the radial ribs, which arise from the lumbar stricture, and lie in the wall of the abdomen, but are absent on the thorax. The shell is usually large, more or less pyramidal or conical, with a wide open terminal mouth. The latter is in Cycladophora simply truncate, whilst in Alacorys it is surrounded by from four to twelve or more terminal feet, prolongations of the abdominal ribs. According to the different number of these (four, five, six, or more) some subgenera may be distinguished, as Tetralacorys, Pentalacorys, Hexalacorys, &c.

Subgenus 1. Tetralacorys, Haeckel, 1881, Prodromus, p. 436.

Definition.—Peristome armed with four feet, opposite in two meridian planes, which are perpendicular to one another.

1. Alacorys lutheri, n. sp. (Pl. 65, fig. 4).

Shell papillate, with distinct collar stricture. Length of the three joints = 3 : 6 : 6, breadth = 3 : 8 : 10. Cephalis subspherical, with a pyramidal horn of the same length. Thorax tuberculate, nearly hemispherical, with circular pores of very different sizes. From the margin of its wide open mouth descend four stout perradial ribs, which are forked at the distal end, and by communication of their fork-branches form the four large, pentagonal holes of the abdomen. From the middle of the lower margin of the holes descend four parallel, vertical, slender feet, about as long as the shell. This species is dedicated to the memory of the great Reformer, Martin Luther.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.06; breadth, a 0.03, b 0.08, c 0.1.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

2. Alacorys tetracantha, Haeckel.

Podocyrtis tetracantha, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xiii. fig. 2.

? Podocyrtis parvipes, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xiv. fig. 5.

Shell rough, with distinct collar stricture. Length of the three joints = 1 : 3 : 5, breadth = 1 : 4 : 6. Cephalis subspherical, with a rudimentary conical horn. Thorax campanulate, with irregular, roundish pores of different sizes. Abdomen inflated, with a small number of very large irregular holes, intermingled with smaller roundish holes. From the margin of the wide open mouth descend, nearly vertically, four strong vertical feet, which are about as long as the shell, and slightly curved, with convex outlines. Podocyrtis parvipes of Ehrenberg seems to be only a mutilated specimen of this species.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.09; breadth, a 0.03, b 0.08, c 0.13.

Habitat.—Fossil in Barbados.

Subgenus 2. Pentalacorys, Haeckel, 1881, Prodromus, p. 436.

Definition.—Peristome armed with five feet, one of which is odd and occipital, the other four paired and lateral.

3. Alacorys pentacantha, Haeckel.

Podocyrtis pentacantha, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xvii. fig. 1.

Shell rough, with slight collar stricture. Length of the three joints = 1 : 2 : 3, breadth = 1 : 4 : 6. Cephalis subspherical, with a rudimentary conical horn. Thorax campanulate, with subregular, circular, quincuncial pores. Abdomen wider, campanulate, with a small number of very large and irregular, roundish holes. From the peristome descend five stout conical feet, which are slightly curved and divergent, nearly as long as the shell.

Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.06; breadth, a 0.025, b 0.08, c 0.11.

Habitat.—Fossil in Barbados.

4. Alacorys bismarckii, n. sp. (Pl. 65, fig. 3).

Shell spiny, with distinct collar stricture. Length of the three joints = 1 : 4 : 5, breadth = 2 : 7 : 10. Cephalis hemispherical, with a very stout, dimpled, conical horn of the same length. Thorax campanulate, spiny, with regular, circular pores. Abdomen wider, campanulate, with larger conical spines, and a small number of irregular, roundish, very large holes. From the peristome descend, nearly vertically, five very large cylindrical feet, nearly twice as long as the shell; they are S-shaped, curved, spinulate in the distal half, and armed at the proximal base with two stout conical spines, the smaller of which is directed inwards, the larger curved upwards. Dedicated to Prince Otto von Bismarck, the Reconstructor of the German Empire.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.1; breadth, a 0.04, b 0.14, c 0.2.

Habitat.—Western Tropical Pacific (north of New Guinea), Station 220, depth 1100 fathoms.

Subgenus 3. Hexalacorys, Haeckel, 1881, Prodromus, p. 436.

Definition.—Peristome armed with six feet, three of which are primary or perradial (Podocyrtis), the three other alternate, secondary or interradial.

5. Alacorys friderici, n. sp. (Pl. 65, fig. 1).

Shell conical, rough, with sharp collar stricture. Cephalis subspherical, with a large, oblique, prismatic horn, twice the length. Thorax campanulate, with regular, circular pores (six to eight in its length). Abdomen wider, campanulate, with a small number of very large pores (three to four in the course of its length). Peristome with six very large divergent feet, which are about as long as the shell, cylindrical, irregularly curved. The specimen figured was observed living, with expanded pseudopodia. The central capsule exhibited four large pear-shaped lobes, filling up the shell-cavity; each contained an oil-globule in the thoracic part. The undivided cephalic part of the capsule enclosed a nucleus, from which four lobes protruded through the four collar pores into the thorax. Dedicated to Frederick the Great, the Royal Philosopher of Potsdam.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.08; breadth, a 0.04, b 0.09, c 0.14.

Habitat.—North Atlantic, Canary Islands, Lanzerote (Haeckel), surface.

6. Alacorys guilelmi, n. sp. (Pl. 65, fig. 2).

Shell thorny, with distinct collar stricture. Length of the three joints = 1 : 3 : 4, breadth = 2 : 5 : 8. Cephalis hemispherical, with a rudimentary conical horn. Thorax hemispherical, spiny, with regular, circular pores. Abdomen wider, campanulate, papillate, with a small number of very large circular holes. Peristome with six diverging feet, which are about as long as the shell, at the base conical, thickened, and at the distal end curved inwards, with a spinulate knob. Dedicated to the German Emperor, Wilhelm.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.08; breadth, a 0.03, b 0.1, c 0.16.

Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.

7. Alacorys hexacantha, n. sp.

Shell thorny, with slight collar stricture. Length of the three joints = 2 : 5 : 7, breadth = 4 : 10 : 14. Cephalis flat, cap-shaped, with a rudimentary conical horn. Thorax campanulate, with regular, circular pores. Abdomen wider, campanulate, with a small number of very large polygonal pores. Peristome with six large divergent feet, which are longer than the shell, cylindrical, and slightly curved, in the proximal half convex, in the distal half concave.

Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.07; breadth, a 0.04, b 0.1, c 0.14.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

8. Alacorys hexapleura, n. sp.

Shell spiny, with distinct collar stricture. Length of the three joints = 2 : 10 : 8, breadth = 3 : 11 : 10. Cephalis hemispherical, large, hyaline, and thick-walled, with a very stout, conical horn of the same length. Thorax pear-shaped, with numerous, regular, circular pores and conical spines, the size of which increases gradually towards the deep, lumbar stricture. Abdomen truncate, conical, with irregular, roundish pores, and six very strong, straight, divergent ribs, prolonged into six short, conical feet.

Dimensions.—Length of the three joints, a 0.04, b 0.2, c 0.16; breadth, a 0.06, b 0.22, c 0.2.

Habitat.—Fossil in Barbados.

Subgenus 4. Octalacorys, Haeckel.

Definition.—Peristome armed with eight feet, four of which are primary or perradial (corresponding to those of Tetralacorys), the other four alternate, secondary, or interradial.

9. Alacorys aculeata, Haeckel.

Podocyrtis aculeata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 80, Taf. xiii. fig. 3.

Podocyrtis aculeata, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 540, Taf. xxxiii. fig. 34.

Shell spiny, with deep collar stricture. Length of the three joints = 2 : 5 : 8, breadth = 2 : 7 : 10. Cephalis subspherical, with a slender, conical horn of twice the length. Thorax campanulate, thorny, with regular, circular pores. Abdomen wider, campanulate, with a small number of very large, regular, hexagonal meshes, and stout spines in the nodal points. Peristome with eight strong conical feet, which are nearly parallel, little curved (convex at the outside), and sometimes all of the same size (equal to the length of the shell); at other times different, four larger alternating with four smaller feet.

Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.08; breadth, a 0.025, b 0.07, c 0.1.

Habitat.—Fossil in Barbados.

10. Alacorys octacantha, n. sp.

Shell spiny, with deep collar stricture. Length of the three joints = 2 : 8 : 6, breadth = 3 : 7 : 7. Cephalis ovate, with a short, conical horn. Thorax pear-shaped, spiny, with regular, circular pores, similar to Cycladophora erinaceus, Ehrenberg (1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. fig. 2). Abdomen truncate, conical, with irregular, roundish pores, and eight stout, straight, thorny, divergent ribs of equal size, which are prolonged into eight free, conical, spiny feet of the same length.

Dimensions.—Length of the three joints, a 0.04, b 0.16. c 0.12; breadth, a 0.06, b 0.14, c 0.14.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

Subgenus 5. Ennealacorys, Haeckel.

Definition.—Peristome armed with nine feet, three of which are primary or perradial, the other six secondary or interradial.

11. Alacorys enneacantha, n. sp.

Shell papillate, with slight collar stricture. Length of the three joints = 2 : 4 : 8, breadth = 3 : 6 : 9. Cephalis hemispherical, with a stout, conical horn of twice the length. Thorax campanulate, with subregular, circular pores, and small, conical papillæ. Thorax wider, campanulate, with circular pores, and conical papillæ of three times the size. Peristome with nine widely divergent, little curved, conical feet, about as long as the shell. Similar to Podocyrtis ventricosa, Ehrenberg (1875, loc. cit., Taf. xvi. fig. 3), different mainly in the feet.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.03, b 0.06, c 0.09.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

12. Alacorys gigas, n. sp.

Shell thorny, with distinct collar stricture. Length of the three joints = 1 : 4 : 2, breadth = 1 : 5 : 4. Cephalis ovate, with a short, conical horn of about half the length. Thorax campanulate, thorny, with small, regular, circular pores, very similar to Cycladophora gigas, Ehrenberg (loc. cit., 1875, p. 68, Taf. xviii. fig. 1). Abdomen truncate, conical, smooth, with irregular, roundish pores, and nine stout and straight, little divergent ribs, which are prolonged into nine cylindrical, pointed feet of the same length.

Dimensions.—Length of the three joints, a 0.05, b 0.2, c 0.1; breadth, a 0.05, b 0.25, c 0.2.

Habitat.—Fossil in Barbados.

Subgenus 6. Polyalacorys, Haeckel.

Definition.—Peristome with numerous (ten to twenty or more) prominent feet, three or four of which are primary and perradial, the others secondary and interradial.

13. Alacorys dodecantha, n. sp.

? Podocyrtis schomburgkii, var., Bury, 1862, Polycystins of Barbados, Taf. xii. fig. 3.

Shell smooth, with slight collar stricture. Length of the three joints = 1 : 3 : 4, breadth = 1 : 4 : 7. Cephalis ovate, with a conical horn of the same length. Thorax campanulate, with regular, circular pores. From its margin arise twelve stout, little curved, radial beams, which are widely divergent, and connected in the middle part by a transverse circular ring, so that the abdomen exhibits twelve large triangular holes, and at the peristome, alternating with these, twelve free conical feet of the same length.

Dimensions.—Length of the three joints, a 0.04, b 0.09, c 0.11; breadth, a 0.03, b 0.12, c 0.22.

Habitat.—Central Pacific, Station 263, depth 2650 fathoms; also fossil in Barbados.

14. Alacorys carcinus, n. sp. (Pl. 74, fig. 9).

Calocyclas carcinus, Haeckel, 1879, Atlas, loc. cit.

Podocyrtis schomburgkii, var., Bury, 1862, Polycystins of Barbados, pl. i. fig. 2; pl. xii. fig. 4.

Shell rough, with distinct collar stricture. Length of the three joints = 1 : 4 : 4, breadth = 2 : 6 : 6. Cephalis hemispherical, with a large, cylindrical, bent spine of three times the length. Thorax inflated, campanulate, with large, regular, circular pores. Abdomen truncate, conical, with three to four transverse rows of regular, square pores, produced by eighteen divergent, straight ribs, which are connected by three to four horizontal rings. Distal end of the ribs prolonged into eighteen slender, conical feet, which are about as long as the thorax and slightly curved inwards.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.08; breadth, a 0.05, b 0.12, c 0.12.

Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms; also fossil in Barbados.

15. Alacorys polyacantha, n. sp.

Shell spiny, with deep collar stricture. Length of the three joints = 3 : 9 : 10, breadth = 4 : 12 : 16. Cephalis hemispherical, with a stout conical horn of the same length. Thorax campanulate, with regular, circular pores and conical spines, increasing in size towards the deep lumbar stricture. Abdomen truncate, conical, with twenty to thirty divergent, straight ribs, which are connected by four to six transverse rings, and prolonged into free conical feet of half the length. Therefore four to six transverse rings of regular, square pores occur.

Dimensions.—Length of the three joints, a 0.03, b 0.09, c 0.1; breadth, a 0.04, b 0.12, c 0.16.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

16. Alacorys ornata, Haeckel.

Cryptoprora ornata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. v. fig. 8.

Shell ovate, smooth, without external strictures, but with two internal annular septa. Length of the three joints = 3 : 5 : 4, breadth = 3 : 6 : 5. Cephalis subspherical, partly enclosed by the uppermost part of the thorax, without horn, or with a small rudimentary horn. Pores subregular, circular, half as broad in the cephalis as in the two other joints. Thorax campanulate. Abdomen truncate, with eighteen to twenty-four parallel, vertical, longitudinal ribs, which are prolonged into slender, free, conical feet of the same length. (This remarkable species may be derived from Carpocanium by apposition of a third joint.)

Dimensions.—Length of the three joints, a 0.03, b 0.05, c 0.04; breadth, a 0.03, b 0.06, c 0.05.

Habitat.—Fossil in Barbados.

Genus 604. Cycladophora,^[221] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with four to six or more radial ribs in the abdomen, the terminal mouth of which is truncate, without feet.

The genus Cycladophora differs from the preceding Alacorys, its probable ancestral genus, in the absence of free terminal feet, the radial ribs of the abdomen being connected by transverse beams throughout their whole length. The number of the regularly disposed ribs (four to six or more) may also here be used for the distinction of different subgenera.

Subgenus 1. Lampterium, Haeckel, 1881, Prodromus, p. 434.

Definition.—Abdomen with four radial ribs, opposite in pairs in two meridian planes, perpendicular one to another.

1. Cycladophora gœtheana, n. sp. (Pl. 65, fig. 5).

Shell shaped like a lantern, with two sharp strictures. Length of the three joints = 1 : 2 : 12, breadth = 1 : 4 : 7. Cephalis hemispherical, with a slender pyramidal horn of three times the length. Thorax twice as large, thorny, hemispherical, with regular, circular pores. Abdomen very long, nearly four-sided prismatic, with four superior smaller, and four inferior larger holes; the former separated by four short, divergent, perradial, the latter by four long, parallel, vertical, interradial bars. Mouth square, four-lobed. Dedicated to Wolfgang Goethe.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.24; breadth, a 0.03, b 0.07, c 0.1 to 0.14.

Habitat.—Central Pacific, Stations 265 to 269, depth 2550 to 2900 fathoms.

2. Cycladophora tetrapleura, n. sp.

Shell very similar to the preceding species, but differing in the following characters: Cephalis conical, with a horn of the same length. Thorax campanulate. Four ribs of the abdomen not parallel and vertical, but more or less divergent. Length of the three joints = 1 : 2 : 8, breadth = 1 : 2 : 4. Whole shell slender, pyramidal. Mouth square, four-lobed.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.24; breadth, a 0.03, b 0.06, c 0.12.

Habitat.—North Pacific, Station 241, depth 2300 fathoms.

3. Cycladophora lanterna, n. sp.

Shell very similar to the two preceding species, but differing in the following characters. Cephalis subspherical, with a thick, pyramidal horn of the same breadth, and three times the length. Thorax hemispherical, with circular, hexagonally-framed pores. Abdomen ovate, with four convex ribs, and twelve large holes, four superior smaller pentagonal, four intermediate very large, ovate, and four inferior, small, triangular holes. Mouth little constricted, nearly circular.

Dimensions.—Length of the three joints, a 0.025, b 0.05, c 0.22; breadth, a 0.025, b 0.08, c 0.11.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

Subgenus 2. Lamptidium, Haeckel.

Definition.—Abdomen with six radial ribs (three primary or perradial, and three alternate, secondary or interradial).

4. Cycladophora hexapleura, n. sp.

Lanterna chinensis, Bury, 1862, Polycystins of Barbados, pl. xiii. fig. 7.

Shell shaped like a lantern, with six sides and two sharp strictures. Length of the three joints = 1 : 2 : 8, breadth = 1 : 2 : 4. Cephalis hemispherical, with a conical spine of the same length. Thorax twice as large, hemispherical, with regular, circular pores. Abdomen nearly six-sided prismatic, with six descending, little curved ribs, and eighteen large holes between them; six superior holes interradial, ovate, six intermediate holes very large, perradial, ovate, six inferior holes triangular, interradial. Mouth six-lobed.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.16; breadth, a 0.03, b 0.06, c 0.1.

Habitat.—Fossil in Barbados.

5. Cycladophora pyramidalis, n. sp.

Podocyrtis sp., Bury, 1862, Polycystins of Barbados, pl. xii. fig. 2.

Shell slender, pyramidal, with six sides and two slight strictures. Length of the three joints = 1 : 4 : 12, breadth = 1 : 4 : 8. Cephalis subspherical, with a conical horn of twice the length. Thorax conical, with regular, circular pores. Abdomen truncate, pyramidal, with six strong, divergent, straight ribs, which are connected by five to six transverse, hexagonal rings; therefore six longitudinal rows of large, roundish, quadrangular meshes (four to five meshes in each row). Mouth hexagonal.

Dimensions.—Length of the three joints, a 0.025, b 0.1, c 0.3; breadth, a 0.03, b 0.1, c 0.2.

Habitat.—Fossil in Barbados.

6. Cycladophora spinosa, n. sp.

Shell spiny, with two deep strictures. Length of the three joints = 1 : 4 : 3, breadth = 1 : 5 : 4. Cephalis subspherical, with a stout conical horn of the same length. Thorax ovate, with regular, circular pores, and numerous conical spines. Abdomen truncate, conical, with irregular, roundish pores, and six strong, divergent ribs. Mouth circular.

Dimensions.—Length of the three joints, a 0.03, b 0.12, c 0.09; breadth, a 0.03, b 0.15, c 0.12.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms; fossil in Barbados.

Subgenus 3. Lamptonium, Haeckel.

Definition.—Abdomen with nine radial ribs (three primary or perradial, and six secondary or interradial).

7. Cycladophora enneapleura, n. sp.

Shell spiny, with two sharp strictures. Length of the three joints = 1 : 5 : 3, breadth = 2 : 7 : 4. Cephalis hemispherical, with a conical horn of twice the length. Thorax campanulate, with regular, circular pores, and conical thorax. Abdomen cylindrical, with nine straight, parallel ribs, and irregular, roundish pores. Mouth circular. (Similar to Cycladophora gigas, Ehrenberg, 1875, loc. cit., Taf. xviii. fig. 1, but differing in the possession of nine abdominal ribs.)

Dimensions.—Length of the three joints, a 0.03, b 0.15, c 0.1; breadth, a 0.06, b 0.2, c 0.12.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

8. Cycladophora nonagona, n. sp.

Shell spiny, with two distinct strictures. Length of the three joints = 3 : 10 : 7, breadth = 2 : 9 : 8. Cephalis pear-shaped, with a stout pyramidal horn of the same length. Thorax pear-shaped, with regular, circular pores, and conical horns, increasing in size towards the base. Abdomen truncate, pyramidal, with nine straight, spinulate ribs, and nine even faces between them, with irregular, roundish pores. Mouth nonagonal.

Dimensions.—Length of the three joints, a 0.06, b 0.2, c 0.14; breadth, a 0.05, b 0.18, c 0.16.

Habitat.—Fossil in Barbados.

Subgenus 4. Cyclampterium, Haeckel.

Definition.—Abdomen truncate, conical or campanulate, with numerous (ten to twenty or more) divergent ribs. Mouth wide open, truncate.

9. Cycladophora pantheon, n. sp. (Pl. 68, fig. 3).

Shell dome-shaped, with slight collar and deep lumbar stricture. Length of the three joints = 1 : 6 : 5, breadth = 1 : 7 : 8. Cephalis small, with a conical horn of the same length. Thorax cupola-shaped, with large, regular, circular pores, and numerous pyramidal tubercles. Abdomen with twelve (sometimes eleven or thirteen) slender, divergent ribs, which are connected at equal distances by four to six horizontal rings, and so produce twelve longitudinal rows of large, regular, square meshes.

Dimensions.—Length of the three joints, a 0.02, b 0.12, c 0.1; breadth, a 0.03, b 0.14, c 0.15.

Habitat.—Central Pacific, Stations 263 to 274, depth 2350 to 2925 fathoms.

10. Cycladophora dodecapleura, n. sp.

Shell cupola-shaped, with two deep strictures. Length of the three joints = 2 : 5 : 6, breadth = 2 : 7 : 10. Cephalis hemispherical, with a conical horn of twice the length. Thorax subspherical, truncate at both poles, thorny, with regular, circular pores. Abdomen in the upper half with a coronal of twelve large ovate holes, separated by twelve divergent, slender ribs, in the lower half with curved, convergent prolongations of the twelve ribs, and numerous small, irregular, roundish pores.

Dimensions.—Length of the three joints, a 0.015, b 0.05, c 0.06; breadth, a 0.02, b 0.07, c 0.1.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

11. Cycladophora campanula, n. sp.

Shell campanulate, with two slight strictures. Length of the three joints = 2 : 4 : 5, breadth = 2 : 6 : 10. Cephalis ovate, with a conical horn of the same length. Thorax campanulate, rough, with regular, circular pores. Abdomen dilated, with fifteen to twenty slender, divergent, little curved ribs, which are connected by two or three horizontal rings, and from two or three transverse rows of large, roundish, square pores.

Dimensions.—Length of the three joints, a 0.04, b 0.08, c 0.1; breadth, a 0.04, b 0.12, c 0.2.

Habitat.—North Atlantic, Bermuda, surface; also fossil in Barbados.

12. Cycladophora spatiosa, Ehrenberg.

Cycladophora spatiosa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. figs. 5, 6.

Shell campanulate, with two slight strictures. Length of the three joints = 2 : 6 : 9, breadth = 3 : 8 : 14. Cephalis subspherical, with a conical horn of the same length. Thorax campanulate, smooth, with regular, circular pores. Abdomen truncate, conical, with sixteen to twenty-four divergent ribs, which are straight or slightly curved, and connected by from four to six transverse, circular rings. The large regular meshes, so produced, form sixteen to twenty-four longitudinal series, and are rounded in the upper, square in the lower transverse rows.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.09; breadth, a 0.03, b 0.08, c 0.14.

Habitat.—Fossil in Barbados.

13. Cycladophora favosa, n. sp. (Pl. 62, figs. 5, 6).

Shell dome-shaped, without collar stricture, but with a deep lumbar stricture. Cephalis flat, cap-shaped, without horn, or with a rudimentary conical horn, with small circular pores. Length of the three joints = 1 : 4 : 3, breadth = 2 : 5 : 4. Thorax subspherical, rough, with regular, circular, hexagonally-framed pores. Abdomen truncate, conical, with eighteen to twenty-four prominent ribs; between every two ribs only two or three ovate pores occur. Mouth circular, with eighteen to twenty-four teeth. The shape of the abdomen is rather variable (figs. 5, 6).

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.06; breadth, a 0.04, b 0.09, c 0.07.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

Subgenus 5. Cyclamptidium, Haeckel.

Definition.—Abdomen nearly cylindrical or prismatic, with numerous (ten to twenty or more) straight, vertical, parallel ribs. Mouth wide open, truncate.

14. Cycladophora fenestrata, n. sp. (Pl. 68, fig. 2).

Shell rough, with two slight strictures. Length of the three joints = 1 : 5 : 5, breadth = 1 : 6 : 5. Cephalis conical, with a conical, dimpled horn of twice the length. Thorax nearly spherical, with regular, circular pores, and small conical spines. Abdomen cylindrical, with eighteen stout, parallel, vertical ribs, which are connected by six to eight horizontal, circular rings; therefore regular transverse and longitudinal rows of square or circular pores occur. Mouth truncate, circular.

Dimensions.—Length of the three joints, a 0.02, b 0.1, c 0.1; breadth, a 0.03, b 0.12, c 0.1.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

15. Cycladophora stiligera, Ehrenberg.

Cycladophora stiligera, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. fig. 3.

Shell smooth, with two distinct strictures. Length of the three joints = 2 : 7 : 8, breadth = 2 : 9 : 7. Cephalis subspherical, with a conical horn of twice the length. Thorax subspherical, smooth, with regular, circular pores. Abdomen cylindrical, with twelve parallel, vertical ribs, which are connected by three to four broad, horizontal rings; therefore subregular, transverse, and longitudinal rows of roundish pores are present. Mouth truncate, circular.

Dimensions.—Length of the three joints, a 0.02, b 0.07, c 0.08; breadth, a 0.02, b 0.09, c 0.07.

Habitat.—Fossil in Barbados.

Genus 605. Calocyclas,^[222] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with a simple corona of terminal feet around the truncate mouth. Abdomen not dilated, cylindrical or ovate. No ribs in the shell-wall.

The genus Calocyclas, and the three following closely allied genera, differ from the four preceding genera of Theophormida in the absence of radial or longitudinal ribs in the wall of the thorax and abdomen. These are completely reduced, and their terminal prolongations only remain, forming a simple or double corona around the mouth of the abdomen. They correspond therefore to Carpocanium and Anthocyrtis among the Dicyrtida. In Calocyclas the corona is simple. The mouth is not dilated, but often constricted, and the abdomen is cylindrical or ovate, not conical. The teeth of the corona are usually vertical or convergent.

Subgenus 1. Calocycletta, Haeckel.

Definition.—Thorax and abdomen smooth, without spines or thorns.

1. Calocyclas veneris, n. sp. (Pl. 74, fig. 5).

Shell smooth, with two distinct strictures. Length of the three joints = 1 : 2 : 2, breadth = 1 : 4 : 3. Cephalis ovate, with a large, triangular, prismatic horn of three times the length. Thorax hemispherical; abdomen cylindrical; both with regular, circular pores of equal size. Mouth truncate, with a corona of nine to twelve vertical, lamellar feet, which are as long as the abdomen, rectangular, twice as broad as their distance apart, and truncate at the end.

Dimensions.—Length of the three joints, a 0.03 to 0.04, b 0.06 to 0.08, c 0.04 to 0.06; breadth, a 0.03 to 0.04, b 0.09 to 0.11, c 0.08 to 0.1.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, many stations; surface, and in various depths.

2. Calocyclas virginis, n. sp. (Pl. 74, fig. 4).

Shell smooth, with distinct collar, but indistinct lumbar stricture. Length of the three joints = 1 : 2 : 1, breadth = 1 : 4 : 3. Cephalis ovate, with a slender, conical horn, little shorter than the shell. Thorax subspherical. Abdomen nearly cylindrical, little contracted towards the peristome. Pores regular, circular, twice as broad in the thorax as in the abdomen, where they are separated by slight longitudinal ribs. Corona of the peristome composed of sixteen to twenty-four vertical, lamellar feet, which are longer than the abdomen, rectangular, and truncate at the end.

Dimensions.—Length of the three joints, a 0.04, b 0.08, c 0.05; breadth, a 0.03, b 0.11, c 0.09.

Habitat.—Central Pacific, Station 225, depth 4475 fathoms.

3. Calocyclas minervæ, n. sp.

Shell smooth, with two deep strictures, similar to Cycladophora stiligera. Length of the three joints = 1 : 4 : 3, breadth = 1 : 4 : 3. Cephalis subspherical, with a large, conical horn of three times the length. Thorax subspherical, with small, regular, circular pores. Abdomen cylindrical, with truncate mouth and few irregular pores of different sizes, commonly arranged in three or four subregular, transverse rows, with large intervening distances. Peristome with a corona of twelve to twenty vertical, lamellar feet, which are about as long as the abdomen, and truncate at the end (in Ehrenberg's figure these are broken off).

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.06; breadth, a 0.02, b 0.09, c 0.07.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

4. Calocyclas amicæ, n. sp. (Pl. 74, fig. 2).

Shell smooth, with two slight strictures. Length of the three joints = 2 : 4 : 5, breadth = 2 : 5 : 5. Cephalis subspherical, with a pyramidal horn of the same length. Thorax campanulate-conical; abdomen nearly cylindrical; both with small, subregular, circular pores. Peristome with a corona of twelve to fifteen small, triangular feet, only as large as the thickness of the shell-wall, and separated by distances of twice the size.

Dimensions.—Length of the three joints, a 0.04, b 0.08, c 0.1; breadth, a 0.04, b 0.1, c 0.1.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

5. Calocyclas sacerdotis, n. sp.

Shell smooth, with two deep strictures. Length of the three joints = 1 : 3 : 4, breadth = 1 : 3 : 3. Cephalis ovate, with a pyramidal horn of three times the length. Thorax campanulate, conical; abdomen twice the length, cylindrical; both with small, regular, circular pores. Peristome somewhat constricted, with a corona of nine to twelve conical feet, which are as long as the cephalis, and with the ends curved inwards, protecting the mouth.

Dimensions.—Length of the three joints, a 0.03, b 0.08, c 0.12; breadth, a 0.03, b 0.09, c 0.09.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

6. Calocyclas vestalis, n. sp. (Pl. 74, fig. 3).

Shell smooth, with two deep strictures. Length of the three joints = 1 : 2 : 3, breadth = 1 : 3 : 3. Cephalis subspherical, with a pyramidal horn of twice the length. Thorax campanulate; abdomen nearly cylindrical; both with regular, hexagonal pores, three times as broad as the bars. Peristome constricted, half as broad as the abdomen, with a corona of nine conical, vertical feet as long as the cephalis.

Dimensions.—Length of the three joints, a 0.03, b 0.07, c 0.1; breadth, a 0.035, b 0.1, c 0.1.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Subgenus 2. Calocyclissa, Haeckel.

Definition.—Thorax spiny or thorny; abdomen smooth.

7. Calocyclas turris, Ehrenberg.

Calocyclas turris, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xviii. fig. 7.

Shell with two sharp strictures. Length of the three joints = 1 : 4 : 4, breadth = 1 : 5 : 4. Cephalis hemispherical, with a stout conical horn of the same length. Thorax subspherical, thorny with small, regular, circular, quincuncial pores. Abdomen cylindrical, smooth, nearly hyaline, with very scarce, irregular, widely scattered pores. Peristome with a corona of fifteen to twenty broad, lamellar, vertical, truncate feet, about as long as the abdomen.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.08; breadth, a 0.03, b 0.1, c 0.08.

Habitat.—Fossil in Barbados.

8. Calocyclas hyalogaster, n. sp.

Shell with two sharp strictures. Length of the three joints = 1 : 4 : 6, breadth = 1 : 4 : 3. Cephalis subspherical, with a conical horn of twice the length. Thorax subspherical, thorny, with regular, circular pores. Abdomen cylindrical, smooth, quite hyaline, without any pores. Peristome with a corona of twelve broad, lamellar, vertical, truncate feet, half as long as the abdomen.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.12; breadth, a 0.02, b 0.08, c 0.06.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

9. Calocyclas erinaceus, Haeckel.

Cycladophora erinaceus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. fig. 2.

Shell with two sharp strictures. Length of the three joints = 2 : 9 : 5, breadth = 3 : 9 : 5. Cephalis subspherical, rough, with a short and broad conical horn of half the length. Thorax ovate, densely covered with conical spines as long as the horn, and with regular, circular, quincuncial pores. Abdomen cylindrical, smooth, with irregular roundish pores of different sizes. Peristome with twelve to fifteen vertical, broad, lamellar, truncate feet half as long as the abdomen (in Ehrenberg's figure these are broken off).

Dimensions.—Length of the three joints, a 0.04, b 0.18, c 0.1; breadth, a 0.06, b 0.18, c 0.1.

Habitat.—Fossil in Barbados.

10. Calocyclas gigas, Haeckel.

Cycladophora gigas, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. fig. 1.

Shell with two sharp strictures. Length of the three joints = 2 : 5 : 3, breadth = 2 : 6 : 4. Cephalis subspherical, rough, with a short and broad conical horn of half the length. Thorax subspherical, campanulate, thorny, with subregular, circular pores (smaller and more numerous than in the preceding). Abdomen cylindrical, smooth, with a small number of sparsely disposed, roundish, irregularly scattered pores. Peristome with twenty to thirty short, lamellar, truncate, vertical feet about half as long as the cephalis.

Dimensions.—Length of the three joints, a 0.06, b 0.15, c 0.09; breadth, a 0.06, b 0.18, c 0.12.

Habitat.—Fossil in Barbados.

Subgenus 3. Calocycloma, Haeckel.

Definition.—Thorax smooth; abdomen spiny or thorny.

11. Calocyclas casta, n. sp. (Pl. 73, fig. 10).

Shell ovate, with two sharp strictures. Length of the three joints = 1 : 2 : 8, breadth = 2 : 4 : 8. Cephalis hemispherical, with a strong pyramidal horn of twice the length. Thorax campanulate, smooth, with small, regular, circular pores. Abdomen inflated, subspherical, covered with large conical spines, and large intervening circular pores (four times as broad as the thoracic pores). Mouth constricted, only one-third as broad as the abdomen, with a peristome of nine to twelve conical vertical feet as long as the abdominal spines. (In the specimen figured they were broken off.)

Dimensions.—Length of the three joints, a 0.03, b 0.04, c 0.15; breadth, a 0.04, b 0.08, c 0.15.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

12. Calocyclas pudica, n. sp.

Shell ovate, with two distinct strictures. Length of the three joints = 1 : 3 : 8, breadth = 1 : 4 : 6. Cephalis subspherical, with a conical horn of three times the length. Thorax and abdomen nearly of the same shape as in the preceding species, but more slender and the regular, circular pores of the abdomen only twice as broad as the thoracic pores. Conical spines of the abdomen only half as large, but more numerous. Peristome constricted, half as broad as the abdomen, with sixteen to twenty short, conical, vertical feet as long as the cephalis.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.16; breadth, a 0.025, b 0.08, c 0.12.

Habitat.—Central Pacific Station 266, depth 2750 fathoms.

Subgenus 4. Calocyclura, Haeckel.

Definition.—Thorax and abdomen spiny or thorny.

13. Calocyclas parthenia, n. sp. (Pl. 74, fig. 1).

Shell nearly ovate, with thorny surface, and two slight strictures. Length of the three joints = 1 : 2 : 4, breadth = 2 : 4 : 5. Cephalis hemispherical, armed with numerous short, conical thorns, and with a pyramidal, very large, vertical horn as long as the thorax, and on the basal half as broad as the cephalis. Thorax hemispherical, separated by a slight stricture from the broader, barrel-shaped abdomen, which is a little constricted at the mouth. Teeth of the coronal about twenty, triangular, short, little divergent. Pores circular, somewhat irregular in size, three to four times as broad as the bars, in all three joints nearly of the same shape.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.11; breadth, a 0.05, b 0.1, c 0.12.

Habitat.—Indian Ocean, Cocos Islands, surface (Rabbe).

14. Calocyclas aspasia, n. sp.

Shell ovate, conical, with two deep strictures. Length of the three joints = 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, with a conical horn of twice the length. Thorax and abdomen nearly of the same shape as in the preceding species, but covered with longer conical spines, less numerous, and twice as long as the diameter of the subregular, circular pores. Mouth more constricted, and armed with a coronal of twelve to sixteen broad, lamellar feet, as long as the cephalis, and similar to those of Calocyclas puella (Pl. 74, fig. 5).

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.08; breadth, a 0.03, b 0.08, c 0.1.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

15. Calocyclas monumentum, n. sp. (Pl. 73, fig. 9).

Shell nearly conical, with two very deep strictures, everywhere covered with long, bristle-shaped, divergent spines, about as long as the thorax. Length of the three joints = 1 : 2 : 2, breadth = 1 : 4 : 6. Cephalis nearly spherical, with a very large, three-sided pyramidal horn of twice the length. Thorax and abdomen of similar form, campanulate, with a lower cylindrical, and an upper truncate, conical part. Pores irregular, roundish, in the smaller thorax of slightly different sizes, in the larger abdomen three to four transverse rows of larger pores (six to eight in each row) are separated by numerous much smaller pores. Peristome wide open, with a coronal of twelve large, triangular, vertical feet, nearly as long as the abdomen; in the base of each foot a large, roundish, triangular pore.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.06; breadth, a 0.04, b 0.12, c 0.18.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Genus 606. Clathrocyclas,^[223] Haeckel, 1881, Prodromus, p. 434.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with a simple corona of terminal feet around the dilated mouth. Abdomen dilated, truncate-conical, or discoidal. No ribs in the shell-wall.

The genus Clathrocyclas differs from the preceding closely allied Calocyclas in the dilated mouth and the flatter form of the abdomen, which is usually truncate, conical, or nearly discoidal. The conical thorax is often separated from the flat abdomen by an elegant ribbon of small quadrangular pores. The feet or teeth of the terminal corona are divergent, or even horizontally expanded, whilst in Calocyclas they are usually vertical or somewhat convergent.

Subgenus 1. Clathrocyclia, Haeckel.

Definition.—Shell highly conical, often ovate or slenderly campanulate. Cephalis commonly with a single horn.

1. Clathrocyclas principessa, n. sp. (Pl. 74, fig. 7).

Shell ovate, with two distinct strictures. Length of the three joints = 1 : 2 : 1, breadth = 1 : 2 : 2. Cephalis hemispherical, large, with a pyramidal, occipital horn of the same length. Thorax subspherical, with irregular, circular pores, about as broad as the bars. Abdomen short, widely open with a single transverse row of circular pores, and a coronal of twelve triangular, divergent feet, as long as the abdomen.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.03; breadth, a 0.04, b 0.08, c 0.09.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

2. Clathrocyclas basilea, (Pl. 74, fig. 6).

Shell campanulate, with two deep strictures. Length of the three joints = 2 : 5 : 3, breadth = 3 : 7 : 9. Cephalis hemispherical, with an ovate, oblique horn of the same length. Thorax hemispherical, with subregular, circular pores of the same breadth as the bars. Abdomen short, with two transverse rows of the same pores, and with a coronal of sixteen to twenty ovate, divergent feet, as long as the horn.

Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.03; breadth, a 0.035, b 0.07, c 0.09.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

3. Clathrocyclas fimbriata, Haeckel.

? Halicalyptra fimbriata, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, Taf. ii. fig. 11.

Shell campanulate, with two deep strictures. Length of the three joints = 1 : 3 : 1, breadth = 1 : 3 : 5. Cephalis hemispherical, with a conical horn of twice the length. Thorax hemispherical, in the upper half hyaline, without pores, in the lower half with four to six transverse rows of subregular, circular pores. Abdomen short, suddenly dilated, with one or two transverse rows of larger ovate pores (six to eight in one row), and with a coronal of twelve to fifteen divergent, slender, curved feet, as long as the cephalis. (In the figure of Ehrenberg, seen half from below, the cephalis is not represented.)

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.02; breadth, a 0.02, b 0.06, c 0.1.

Habitat.—Fossil in Barbados.

4. Clathrocyclas collaris, n. sp. (Pl. 74, fig. 8).

Shell subconical, with two indistinct strictures. Length of the three joints = 1 : 1 : 2, breadth = 1 : 2 : 3. Cephalis hemispherical, with a triangular prismatic horn three times the length. Thorax truncate, conical, with a single transverse row of circular pores, each of which is placed in the lower end of an oblong, lanceolate, longitudinal furrow; collar composed of fifteen to twenty such furrows. Abdomen inflated, with four to six transverse rows of circular pores, and with a coronal of nine triangular, divergent feet, longer than the collar.

Dimensions.—Length of the three joints, a 0.02, b 0.03, c 0.06; breadth, a 0.03, b 0.06, c 0.09.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

5. Clathrocyclas puella, Haeckel.

Podocyrtis puella sinensis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xiv. fig. 3.

Shell subconical, with two indistinct strictures. Length of the three joints = 1 : 1 : 2, breadth = 1 : 2 : 3. Cephalis hemispherical, with a pyramidal horn of twice the length. Pores subregular, circular, quincuncial, in the dilated abdomen (with four to five transverse rows), twice to three times as large as in the short thorax (with two to three rows). Coronal of the wide peristome with fifteen to twenty short, triangular, divergent feet, about as long as the cephalis.

Dimensions.—Length of the three joints, a 0.02, b 0.02, c 0.04; breadth, a 0.02, b 0.04, c 0.06.

Habitat.—Fossil in Barbados.

6. Clathrocyclas domina, Haeckel.

Podocyrtis domina sinensis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xiv. fig. 4.

Shell subconical, with two slight strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 4. Cephalis ovate, with a conical horn of the same length (and sometimes with some little accessory thorns at its base). Pores subregular, circular, quincuncial, in the dilated abdomen (with six to eight transverse rows), twice to four times as large as in the hemispherical thorax (with four to six rows). Coronal of the wide peristome with nine to twelve short, triangular, divergent feet, half as long as the cephalis (in Ehrenberg's figure incomplete).

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.02, b 0.06, c 0.08.

Habitat.—Central Pacific, Stations 263 to 268, depth 2650 to 3000 fathoms; also fossil in Barbados.

Subgenus 2. Clathrocycloma, Haeckel.

Definition.—Shell flatly conical, often widely campanulate, or nearly discoidal. Cephalis commonly with two or more horns.

7. Clathrocyclas alcmenæ, n. sp. (Pl. 59, fig. 6).

Shell conical, with two indistinct strictures. Length of the three joints = 2 : 10 : 1, breadth = 2 : 12 : 14. Cephalis hemispherical, with two divergent, pyramidal horns; frontal horn as long as the cephalis, occipital horn of twice the length. Thorax conical, with large hexagonal meshes, increasing gradually in size towards the short abdomen, which is represented only by a single circular girdle of small, square, abdominal pores. Coronal of the peristome with twenty to thirty triangular, divergent, nearly horizontal feet, as long as the cephalis.

Dimensions.—Length of the three joints, a 0.02, b 0.1, c 0.01. breadth, a 0.02, b 0.12, c 0.14.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

8. Clathrocyclas europæ, n. sp. (Pl. 59, figs. 11, 12).

Shell conical, almost of the same form as the preceding nearly allied species, differing from it in the concave (not straight) outline of the flatter conical thorax, in the more rounded form of its pores, and in the subspherical form of the cephalis, bearing only a single conical horn of the same length. Length of the three joints = 2 : 8 : 1, breadth = 2 : 12 : 14. In fig. 11 the cephalis is broken off, so that the four cortinar pores are visible (two smaller jugular and two larger cardinal pores, separated by two coracal beams).

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.01. breadth, a 0.02, b 0.12, c 0.14.

Habitat.—Mediterranean, Corfu (Haeckel), surface.

9. Clathrocyclas semeles, n. sp. (Pl. 58, fig. 5).

Shell conical-campanulate, with two distinct strictures. Length of the three joints = 2 : 8 : 1, breadth = 2 : 8 : 10. Cephalis hemispherical, with three divergent, conical horns (the caudal horn, directed downwards, much longer than the occipital and frontal horns). Pores of the thorax large, roundish. Abdomen (as in the two preceding species) with only a single circle of forty to fifty small square pores. Coronal with about the same number of short, triangular, almost horizontally divergent feet.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.01. breadth, a 0.02, b 0.08, c 0.1.

Habitat.—Central Pacific, Station 271, surface.

10. Clathrocyclas danaës, n. sp. (Pl. 59, figs. 13, 14).

Shell flatly conical, with straight outline (as in Clathrocyclas alcmenæ, Pl. 59, fig. 6). Length of the three joints = 1 : 5 : 1, breadth = 2 : 8 : 1. Cephalis hemispherical, with a single, short, conical, oblique horn (broken off in the specimen figured). Pores of the thorax polygonal, increasing gradually in size towards the girdle (in three to four circles.) Abdomen nearly horizontally expanded with two rows of pores, the inner with very small and numerous square pores, the outer with twenty to thirty much larger quadrangular pores. Coronal of the peristome with the same number of short, divergent feet, alternating with the larger pores.

Dimensions.—Length of the three joints, a 0.02, b 0.1, c 0.02; breadth, a 0.04, b 0.15, c 0.2.

Habitat.—North Atlantic, Canary Islands (Lanzerote), Station 354, surface.

11. Clathrocyclas jonis, n. sp. (Pl. 59, fig. 9).

Shell campanulate, with two slight strictures. Length of the three joints = 1 : 5 : 2, breadth = 1 : 6 : 8. Cephalis small, hemispherical, with two divergent, conical horns of nearly equal length. Pores of the thorax polygonal, increasing in size towards the girdle; in the upper half filled up by an extremely fine and delicate cobweb-like network. Abdomen with two rows of pores, of the same shape as in the preceding species, also with equal coronal.

Dimensions.—Length of the three joints, a 0.03, b 0.1, c 0.03; breadth, a 0.02, b 0.12, c 0.16.

Habitat.—Central Pacific, Station 274, surface.

12. Clathrocyclas latonæ, n. sp. (Pl. 59, fig. 7).

Shell campanulate, very similar to the preceding species, but flatter and different in the larger cephalis, bearing only a single oblique horn. All the polygonal pores of the thorax are filled out by delicate cobweb-like network. Length of the three joints = 1 : 3 : 1, breadth = 1 : 4 : 6. Abdomen with three circular rows of quadrangular pores; first very small and numerous, second of median size, third very large. Coronal with thirty to forty short triangular feet.

Dimensions.—Length of the three joints, a 0.03, b 0.08, c 0.03; breadth, a 0.03, b 0.12, c 0.18.

Habitat.—Tropical Atlantic, Station 325, surface.

13. Clathrocyclas coscinodiscus, n. sp. (Pl. 58, figs. 3, 4).

Shell flatly campanulate, with two distinct strictures. Length of the three joints = 1 : 5 : 2, breadth = 1 : 8 : 10. Cephalis hemispherical, with two divergent, pyramidal horns of the same length. Thorax with concave outline, with numerous hexagonal pores, gradually increasing in size towards the girdle, except the outermost row (inside the girdle), which is composed of very small, square pores. Abdomen (outside the girdle) with three rows of pores; first with small, second with median, third with large pores. Coronal with eighty to one hundred short, divergent feet.

Dimensions.—Length of the three joints, a 0.02, b 0.1, c 0.03; breadth, a 0.025, b 0.16, c 0.2.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

14. Clathrocyclas cassiopeiæ, n. sp. (Pl. 59, fig. 5).

Shell flatly campanulate, with two slight strictures. Length of the three joints = 2 : 4 : 3, breadth = 2 : 6 : 8. Cephalis ovate, thorny, with a pyramidal horn of the same length, and several smaller accessory horns. Thorax smooth, with irregular, polygonal pores of nearly equal size. Abdomen spiny, with three to four irregular rows of similar pores. Coronal with sixty to ninety or more irregularly and obliquely divergent feet, little larger than the abdominal spines.

Dimensions.—Length of the three joints, a 0.04, b 0.08, c 0.06; breadth, a 0.03, b 0.12, c 0.16.

Habitat.—Indian Ocean, Madagascar, Rabbe, surface.

Genus 607. Lamprocyclas,^[224] Haeckel, 1881, Prodromus, p. 434.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with a double corona of solid terminal feet around the mouth. No ribs in the shell-wall.

The genus Lamprocyclas differs from Calocyclas, its ancestral form, in the duplication of the terminal corona. Usually the feet or teeth of the lower corona are convergent and curved inwards, whilst the teeth of the upper corona are divergent and curved outwards. Sometimes above the latter a third corona begins to be developed. The whole shell is more or less conical, very thick-walled, with a large and stout apical horn.

Subgenus 1. Lamprocyclia, Haeckel.

Definition.—Feet of the peristome simple, not branched.

1. Lamprocyclas nuptialis, n. sp. (Pl. 74, fig. 15).

Shell campanulate, nearly smooth, with two slight strictures. Length of the three joints = 1 : 2 : 2, breadth = 1 : 3 : 4. Cephalis ovate, with a very large, three-sided prismatic horn, nearly as long as the shell. Thorax and abdomen gradually dilated, with regular, circular, double-edged pores. Outer coronal of the peristome with twelve to fifteen divergent feet, inner with as many subvertical, triangular, little curved feet, about as long as the cephalis.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.06; breadth, a 0.03, b 0.09, c 0.12.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

2. Lamprocyclas maritalis, n. sp. (Pl. 74, figs. 13, 14).

Shell campanulate, very similar to the preceding species in form and fenestration, but not so slender and with different peristome. Length of the three joints = 4 : 5 : 6, breadth = 4 : 10 : 13. Cephalis subspherical, with a very stout, pyramidal horn of twice the length, the edges of which are spirally convoluted. Outer coronal of the peristome with twelve to fifteen short, divergent feet, inner with as many convergent, longer feet.

Dimensions.—Length of the three joints, a 0.04, b 0.05, c 0.06; breadth, a 0.04, b 0.1, c 0.13.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

3. Lamprocyclas deflorata, n. sp. (Pl. 74, fig. 10).

Shell ovate, smooth, with deep collar, but indistinct lumbar stricture; very similar to the two preceding species, but with different horn and peristome. Length of the three joints = 3 : 5 : 8, breadth = 3 : 10 : 13. Cephalis subspherical, with a pyramidal horn of twice the length, the three faces of which are deeply concave. Thoracic pores half as large as the abdominal, both subregular, double-edged. Outer coronal of the wide peristome with nine short, triangular, subvertical feet, inner with nine larger, horizontal feet, lying in the plane of the wide mouth.

Dimensions.—Length of the three joints, a 0.03, b 0.05, c 0.08; breadth, a 0.03, b 0.1, c 0.13.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

4. Lamprocyclas saltatricis, n. sp. (Pl. 74, fig. 16).

Shell conical, rough, with two slight strictures. Length of the three joints = 2 : 2 : 3, breadth = 1 : 4 : 6. Cephalis ovate, with a large, prismatic horn, half as long as the shell. Pores subregular, circular, not double-edged, three times as broad in the inflated abdomen as in the hemispherical thorax. Outer coronal of the wide peristome with twelve to fifteen divergent feet, inner with fifteen to twenty conical feet, which are curved inwards nearly horizontally.

Dimensions.—Length of the three joints, a 0.04, b 0.05, c 0.07; breadth, a 0.025, b 0.1, c 0.15.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Lamprocyclas reginæ, n. sp. (Pl. 74, figs. 11, 12).

Shell campanulate, with two slight strictures. Length of the three joints = 2 : 3 : 3, breadth = 2 : 5 : 6. Cephalis subcylindrical, with about fifteen longitudinal rows of circular pores, separated by prominent, parallel crests, and with a very large sword-like horn, nearly as long as the shell. Thorax hemispherical, smooth, with elegant, circular, hexagonally-framed pores. Abdomen dilated, with similar but larger pores, armed with hook-shaped spines. The two inferior rows of these hooks form the double coronal of the peristome; the feet of the outer are curved downwards, of the inner inwards.

Dimensions.—Length of the three joints, a 0.04, b 0.06, c 0.06; breadth, a 0.04, b 0.1, c 0.12.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.

6. Lamprocyclas ægles, Haeckel.

Podocyrtis ægles, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B. B iv. fig. 18.

Shell campanulate, conical, thorny, with two deep strictures. Length of the three joints = 3 : 5 : 5, breadth = 3 : 8 : 11. Cephalis ovate, with a stout, three-sided prismatic horn of twice the length. Pores subregular, circular, twice as broad in the inflated abdomen as in the campanulate thorax, and four times as broad as in the cephalis. Outer coronal of the wide peristome with fifteen to twenty conical, divergent feet, inner coronal with a smaller number of vertical, parallel, divergent feet.

Dimensions.—Length of the three joints, a 0.03, b 0.05, c 0.05; breadth, a 0.03, b 0.08, c 0.11.

Habitat.—North Atlantic, depth 1400 fathoms (Berrymann).

Subgenus 2. Lamprocycloma, Haeckel.

Definition.—Feet of the peristome forked or branched.

7. Lamprocyclas bajaderæ, n. sp.

Shell campanulate, very similar to the preceding species, but with stronger spines on the abdomen and with different peristome. Length of the three joints = 2 : 2 : 3, breadth = 2 : 6 : 8. Cephalis equal to that of Lamprocyclas maritalis (Pl. 74, figs. 13, 14). Outer coronal of the peristome with fifteen to twenty divergent, pyramidal feet, half as long as the horn; inner coronal with as many longer, vertical feet, which are irregularly forked or branched.

Dimensions.—Length of the three joints, a 0.04, b 0.04, c 0.06; breadth, a 0.04, b 0.12, c 0.16.

Habitat.—South Pacific, Station 298, depth 2225 fathoms.

Genus 608. Diplocyclas,^[225] Haeckel, 1881, Prodromus, p. 434.

Definition.—Theophormida (vel Tricyrtida multiradiata aperta) with a double corona of radial solid feet, an upper around the lumbar stricture, a lower around the mouth. No ribs in the shell-wall.

The genus Diplocyclas differs from all the other Theophormida in the possession of a double coronal of radial teeth, an upper between thorax and abdomen, and a lower around the terminal mouth of the latter; it may be regarded as an Anthocyrtis, which has formed an abdomen, and repeated the terminal armature. The cephalis bears a single or double apical horn.

1. Diplocyclas bicorona, n. sp. (Pl. 59, fig. 8).

Shell slender, campanulate. Length of the three joints = 1 : 3 : 2, breadth = 1 : 4 : 4. Cephalis subspherical, with two divergent horns; the occipital of the same length and forked, the frontal shorter and simple. Thorax campanulate, with six to eight transverse rows of double-edged roundish pores of increasing size. Abdomen cylindrical, with three transverse rows of large polygonal pores, and a terminal row of very small square pores. Lumbar and terminal coronals of similar shape, each with twenty to thirty short divergent feet.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.04; breadth, a 0.025, b 0.08, c 0.08.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

2. Diplocyclas bicincta, n. sp.

Shell campanulate, in general of the same form as, and similar fenestration to, the preceding species but not so slender, and with different proportions. Length of the three joints = 1 : 4 : 2, breadth = 2 : 5 : 5. Cephalis hemispherical, with a single, conical, simple horn. Pores of the thorax hexagonal, of increasing size (in eight to ten transverse rows). Abdomen with smaller square pores (in four to six rows). The two coronals of the same shape as in Pl. 59, fig. 8.

Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.04; breadth, a 0.04, b 0.1, c 0.1.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

3. Diplocyclas bizonalis, n. sp.

Shell subconical, with indistinct collar and distinct lumbar stricture. Length of the three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with two divergent conical horns of equal size. Thorax conical, with small, irregular, double-edged pores, and a terminal corona of about nine very large pores. Abdomen truncate, conical, with three to four transverse rows of roundish, quadrangular, very large pores. Lumbar and terminal coronals of similar shape, each with twelve to fifteen triangular divergent feet.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.06; breadth, a 0.02, b 0.06, c 0.08.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

Subfamily 2. Theophænida, Haeckel, 1881, Prodromus, p. 437.

Definition.—Phormocyrtida with the basal mouth of the shell fenestrated (vel Tricyrtida multiradiata clausa).

Genus 609. Hexalatractus,^[226] n. gen.

Definition.—Theophænida (vel Tricyrtida multiradiata clausa) with six lateral wings on the abdomen.

The genus Hexalatractus, and the following genus Theophæna, represent together the small subfamily Theophænida, or those Tricyrtida in which the terminal mouth of the shell is closed by lattice-work, and six or nine lateral apophyses indicate a multiradiate structure. The shell is more or less ovate or spindle-shaped, tapering towards both poles, and resembles greatly the triradiate Rhopalocanium. It may be derived from the latter by interpolation of three secondary or interradial wings between the three primary or perradial apophyses.

1. Hexalatractus sexalatus, n. sp.

Shell ovate, smooth, with two distinct strictures, length of the three joints = 3 : 6 : 9, breadth = 4 : 9 : 8. Cephalis subspherical, with a pyramidal horn of twice the length. Thorax campanulate; abdomen inversely conical; both with subregular, circular pores. Six divergent wings arise, beginning from the collar stricture, from the upper half of the shell, with broad triangular base; they are little curved downwards, with the convexity outside, and gradually tapering towards the distal end; the latter lies in the same horizontal plane as the basal apex of the abdomen.