1. Family BALANIDÆ, (or Sessile Cirripedes). (continued 4)

I have formed my single sub-province for the southern extremity of Africa; for although I know of only 11 species from this comparatively short and uniform line of coast, yet I was not able to group these eleven in any of the main provinces: 5 of the species are peculiar, 1 Australian, 3 European and West Indian, and 2 almost universally distributed.

The second province includes the west coast of North and South America, from Tierra del Fuego to Behring’s Straits: on this enormously long line of coast, only 22 species are known to exist, but of these no less than 15 are peculiar. Of these 15, four are not found south of the torrid equatorial region, and eight are not known to occur north of this same region; so that this long line of coast might have been divided into two sub-provinces, of which the southern would have been the most peculiar; but as eight species are found both north and south of the equatorial region, I have not made this sub-division. Two of the species occurring on the western coast of North America, seem to represent species found on its eastern coast, and in Europe; thus, Balanus glandula takes the places of B. crenatus, and B. cariosus that of B. balanoides. Not a single species, excepting a few which are also widely distributed over other parts of the world, is known to be common to the east and west coasts of the two Americas.

The third province is that of the East Indian Archipelago, and includes the Philippines, Borneo, New Guinea, Sumatra, Java, Malacca, and the eastern coast of India. Here we find 37 species, of which 24 are peculiar. I may remark, that I have received no species from Madagascar or the eastern coast of Africa; few from India, or from the coast of China; and I suspect, that on most of these coasts, only few exist. Probably our third province will hereafter be found to include the whole Indian Ocean.

The fourth province is that of Australia, including New Zealand: it has 30 species, of which 21 are peculiar. Had the temperate Australian coasts (i. e., those south of the isocryme of 68°) been alone considered, the number of the species would have been probably 25, of which 20 would have been peculiar,—that is, if we admit within the 20, several species which range from the temperate into the torrid zone, but do not extend beyond the Australian shores. Owing to the widely-extended ranges of most Cirripedes, no Arctic or Antarctic provinces can be said to exist.

To recapitulate the above results, bearing in mind that, although the total number of known existing Cirripedes is 147, yet that the habitats of seven are unknown, and that eighteen are excluded owing to their being attached to floating or swimming objects, so that there are only 122 species referred to in the following table:

Total number of species. Species confined to the province.

(1.) First, or North Atlantic Province, to lat. 30° N. (If the West Indies had been included the numbers would have been 42 and 28) 31 22

(2.) Sub-province of South Africa 11 5

(3.) Second province, or West Coast of North and South America 22 15

(4.) Third province, or East Indian Archipelago 37 24

(5.) Fourth, or Australian province 30 21

The least prolific of these provinces contains 22 species, or between 1/5th and 1/6th of the total number of species, and the most prolific between 1/3rd and 1/4th of this same number. In each of these provinces, it is remarkable that the peculiar species are very nearly two thirds of the whole of its inhabitants. These facts, I think, show that the above provinces are natural divisions of the world, as far as their Cirripedial inhabitants are concerned.

As Cirripedes belong to the great class of Crustacea, and as the distribution of the latter has lately been fully discussed by Mr. Dana, it may be worth while briefly to compare my results with his; more especially as they are so very different. I should premise, as perhaps accounting to a certain extent for this difference, that, owing to the wide range of many species, and the almost universal extension of the same genera, my provinces are founded merely on a certain proportion of the species, namely, two thirds, being peculiar or confined to a region of considerable dimensions: whereas, in the case of ordinary Crustaceans, the greater number of the species are distinct even in the sub-provinces, and the provinces are founded mainly on generic differences. Mr. Dana divides the surface of the globe into three great sections, or provinces, the Africo-Europæan, the extent of which is shown by its title; the Occidental, which includes both the east and west coast of both Americas; and the Oriental, including the Indian and Pacific Oceans, with the East Indian Archipelago, and Australia. Thus Mr. Dana entirely separates the Eastern shores of North America from Europe; whereas, as far as their Cirripedial inhabitants are concerned, they are most intimately allied, and form my first or North Atlantic province; and to this, as I have shown, even the West Indies, the coast of Brazil, and equatorial West Africa might have been added. It follows, from this similarity in the Cirripedes on the two sides of the Atlantic, and from their dissimilarity with those on the shores of the Pacific, that the east and west coasts of the two Americas form two quite distinct Cirripedial provinces; though, in the northern half, some connection is shown by a few representative species: on the other hand, Mr. Dana unites both sides of the whole American continent, into his single Occidental province. The South-African province is not brought out by Mr. Dana so prominently, as I have found necessary. Mr. Dana joins the East Indian Archipelago and Australia into his single Oriental province, and makes New Zealand, as a sub-province, apparently as distinct from Australia, as Australia is from the East Indian Archipelago: whereas I find that the Cirripedes of New Zealand clearly belong to Australia; and that the Australian Cirripedes, especially if the temperate shores be alone considered, are as distinct from those of the East Indian Archipelago, as from those of any other quarter of the whole world. I believe that the provinces deduced from the distribution of Cirripedes, accord better with the Molluscan provinces, than with those given by Mr. Dana for the rest of the great class of Crustaceans.

In the following tables, an asterisk means that the species is not found in any other distinct region of the globe. When found in one of the five provinces, a corresponding number, within brackets, is appended, to show in which province or sub-province it has been found.

(1.) FIRST OR NORTH ATLANTIC PROVINCE: Europe and the Eastern United States, from the Arctic Regions to 30° north latitude.

Balanus tintinnabulum(1 to 5).

tulipiformis*confined to Europe.

calceolusEurope and India.

galeatus*confined to North America and West Indies.

spongicola(2) and West Indies (?).

perforatus*confined to Europe, but possibly in the West Indies.

amphitrite(1 to 5).

eburneus*confined to North America and West Indies.

improvisusEurope and North America and (3).

porcatus*Europe and North America.

crenatus””W. Indies and (2).

balanoides*””

Hameri*””

Acasta spongitesEurope and (2).

cyathus*Madeira and West Indies.

Pyrgoma anglicum*confined to Europe, but ranges as far at least as the Cape de Verde Islands.

Xenobalanus globicipitis*confined to Europe.

Chthamalus stellatusEurope and North America and (3 and 4).

Pachylasma giganteum*confined to Europe.

Verruca StrömiaEurope and Red Sea.

Spengleri*Madeira.

Pœcilasma aurantia*”

crassa*”

Dichelaspis Lowei*”

Oxynaspis celata*”

Alepas minuta*Europe.

parasita*Europe and Atlantic Ocean.

Anelasma squalicola*Europe.

Alcippe lampas*”

Scalpellum vulgare*”

Pollicipes cornucopia*”

Here we have 31 species, of which 22 are not found in any other great region of the world.

(2.) SUB-PROVINCE: Africa, South of lat. 30°.

Balanus tintinnabulum(1 to 5).

Capensis*

spongicola(1) and West Indies (?).

amphitrite(1 to 5).

crenatus(1) and West Indies.

Acasta spongites(1).

Tetraclita serrata*

rosea(4).

Chthamalus dentatus*also on West Coast of Africa.

Octomeris angulosa*

Scalpellum ornatum*

In this small region we have only 11 species, of which five are peculiar: Balanus Capensis and Tetraclita serrata, seem to be representatives of B. psittacus of S. America and of T. porosa of that and several other regions.

(3.) SECOND PROVINCE: West Coast of South and North America, from Tierra del Fuego to Behring’s Straits.

Balanus tintinnabulumnorth and south of the equator (1 to 5).

psittacus*south.

vinaceus*”

trigonusnorth and south (4 and 5).

lævis*”

concavus”(4 and 5).

pœcilus*south.

improvisussouth (and north?) (1).

nubilus*north.

glandulanorth, and Southern Pacific Ocean.

cariosus*north.

Tetraclita porosanorth and south (4 and 5 and W. Indies).

Elminius Kingii*south.

Chthamalus stellatusnorth.

cirratus*south.

scabrosus*”

fissus*north and south.

Hembeli*north.

Verruca lævigata*south.

Pollicipes elegans*south and north.

polymerus*”

Cryptophialus minutus*south.

Here we have on this long line of coast, 22 species, of which 15 are peculiar.

(4.) THIRD PROVINCE: Indian Archipelago (including the Philippines, Malacca, Borneo, Sumatra, Java, and New Guinea, and eastern coast of India).

Balanus tintinnabulum(1 to 5).

Ajax*

navicula*

stultusand West Indies.

trigonus(3 and 5).

concavus(3 and 5).

amphitrite(1 to 5).

patellaris*

amaryllis(5).

quadrivittatus*

Acasta lævigataand Red Sea.

fenestrata*

purpurata*

sporillus*

Tetraclita porosa(3 and 5) and West Indies.

costata*

vitiata(5).

cœrulescensPacific Ocean.

radiata(5) and West Indies.

Pyrgoma cancellatum*

grande*

milleporæ*

crenatum*

monticulariæ*

Creusia spinulosaand West Indies.

Chthamalus stellatus(1 and 3).

intertextus*

Chamæsipho scutelliformis*

Octomeris brunnea

Pœcilasma fissa*

eburnea*

Dichelaspis Warwickii*

Ibla Cumingii*

Scalpellum rostratum*

Pollicipes mitella*

Lithotrya Nicobarica*

truncataand Pacific Ocean.

Here we have 37 species, of which 24 are peculiar to this province.

(5.) FOURTH PROVINCE: Australia (including New Zealand).

Balanus tintinnabulum(1 to 5).

nigrescens*

decorus*

trigonus(3 and 4).

concavus(3 and 4).

amphitrite(1 to 5).

amaryllis(4).

allium*

vestitus*

imperator*

Acasta sulcata*

glans*

Tetraclita porosa(3 and 4).

rosea(2).

purpurascens*

vitiata(4).

radiata(4) and West Indies.

Elminius plicatus*

simplex*

modestus*

Chthamalus antennatus*

Chamæsipho columna*and Pacific Ocean (?).

Pachylasma aurantiacum*

Catophragmus polymerus*

Alepas tubulosa*

Ibla quadrivalvis*

Scalpellum Peronii*

Pollicipes spinosus*

sertus*

Lithotrya cauta*

Here we have 30 species, of which 21 are peculiar.

Geological History.

The ancient history of the Balanidæ is a brief one. No secondary species has hitherto been discovered; in my monograph on the fossil Lepadidæ[80] I have shown that the negative evidence in this case is of considerable value, and consequently that there is much reason to doubt whether any member of the family did exist before the Eocene period. The existence of a Cretaceous Verruca is an apparent exception to the rule, as this genus has hitherto always been ranked amongst sessile cirripedes; but Verruca, as we now know, must be placed in a family by itself, quite distinct from the Balanidæ. Balanus is the oldest genus as yet known; it first appeared in Europe and North America, during the deposition of the eocene beds; and was at that time, as far as our information at present serves, represented by very few species. In South America, one species of Balanus abounds in individuals in the ancient Patagonian tertiary formation. I have seen, in the British Museum, specimens, said to have come from the eocene nummulitic beds near the mouth of the Indus, belonging to the second section of the genus. Generally, the extinct forms belong to the last section of this genus, which has the parietes not permeated by pores. During the miocene and pliocene ages, sessile cirripedes abounded. No extinct genus in this family has hitherto been discovered. It is singular, that though the Chthamalinæ approach much more closely than do the Balaninæ to the ancient Lepadidæ, of which so many species have been found fossil even in the older Secondary formations, yet that only one species of one genus of this sub-family has been hitherto found in any deposit; and that species is the still existing Pachylasma giganteum, in the modern beds of Sicily. During the epoch of the Glacial deposits in Scandinavia, Scotland, and Canada, the still existing species seem to have abounded; and they attained larger average dimensions than the same species now do on the shores of Great Britain, or even on the shores of the northern United States, where the average size seems larger than on this side of the Atlantic.

Under the genus Balanus, I have given my reasons for never naming species in this large and difficult genus, without examining the opercular valves: it has been owing to this, as it appears to me, proper want of caution, that there are so many nominal species. Thus it is made to appear in catalogues, that the tertiary seas abounded with species of Balanus to an extent now quite unparalleled in any quarter of the world. Bronn,[81] for instance, in his invaluable ‘Index Palæontologicus,’ gives the names of 35 Balani, found fossil in Europe, and I have not counted those found only in alluvial deposits, as they would certainly be the same as the still living species. Now I know only 11 recent Balani on the shores of all Europe, from the North Pole to lat. 30°; and of these I doubt whether B. balanoides and improvisus have been found fossil. In the Red Crag there is one extinct Balanus: in the Coralline Crag, which seems to have been very favorable to the existence of Cirripedes, there are six species of Balani, of which two are absolutely extinct, and one does not occur in any neighbouring sea: in the Eocene formations the species seem to have been rare, and I have seen only one, and that is an extinct form. Taking these several facts into consideration, and bearing in mind that Cirripedes usually range widely, I do not believe, if all the specimens of Balani hitherto found in the several tertiary formations, from the eocene to the glacial deposits, throughout Europe, were collected together, they would amount to 20 species. I have myself seen, in a recognisable state, only 12 fossil species, of which five are extinct, or not found in any neighbouring sea: I think it probable that three other recent species, viz. B. tulipiformis, perforatus, and amphitrite, may occur in the Mediterranean formations; and this would make 15 species. Therefore in the above estimate of 20 species, five are allowed for species existing in European collections, but not hitherto seen by me; and this, I believe, is a very full allowance. Consequently, even on the supposition that the five species just admitted as possibly existing in cabinets, and that the other five extinct species, which I have seen and examined, have all been previously named by other authors, a supposition excessively improbable, even then there would be 15 superfluous names in Bronn.

The following short table shows how Cirripedes, including all three Families, were represented in Great Britain, throughout the several TERTIARY STAGES.

Name. Living species but found fossil in some tertiary deposit. Mammilliferous crag, and glacial deposits. Red crag. Coralline crag. Eocene.

Balanus tintinnabulum **

calceolus **

spongicola **

concavus * * *

porcatus ***

crenatus ****

Hameri * * *

bisulcatus **

dolosus *

inclusus *

unguiformis *

Acasta undulata *

Pyrgoma anglicum **

Coronula barbara *

Verruca Strömia * * * *

Scalpellum magnum *

quadratum *

Pollicipes reflexus *

Total, 18, recent and extinct, found fossil in Great Britain, in some tertiary deposit 9 5810 3

As affording some standard of comparison by which to compare the number of fossil species, at any period, in relation to the number of species probably existing in the neighbouring seas during the same epoch, I may state that there are now living and propagating on the shores of Great Britain, 18 species belonging to the three Families included in the above table. I have not counted three species, in the genera Alcippe and Conchoderma, which, from the minuteness of their valves, it is hardly possible would be found fossil. On the other hand, I have included in the 18, five species of Lepas, which from floating and being oceanic, are more likely to be cast up on beaches, than to be imbedded in sedimentary deposits; so that 13 would, perhaps, be a safer number, as a standard of comparison. Now in the coralline crag, which seems to have been eminently favorable for the existence and subsequent preservation of Cirripedes, and which has been so well worked, only nine fossil species, as may be seen in the table, have been as yet discovered.