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.
[80] Since the note to page 5 of that work was written, I have been informed that the so-called cretaceous Tubicinella maxima is not a Cirripede.
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.
[81] To save any other person, interested in fossil Cirripedia, going through the several works quoted by Bronn, I have given some remarks on his list of species, in an appendix at the end of the [Balanidæ].
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 | 5 | 8 | 10 | 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.
Sub-Family—BALANINÆ.
Shell with the rostrum having radii, but without alæ; lateral compartments all having alæ on one side and radii on the other side; parietes generally either porose, or longitudinally ribbed on their inner surfaces.