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Show 1867.] DR. BOWERBANK ON HYALONEMA LUSITANICUM. 901 A. Rostrum shorter than peduncle of superior antenna** (six teeth on upper edge) P. siphonocerus, Phil. B. Rostrum longer than peduncle of superior antennae, but shorter than carapace. a. Teeth on the under edge (filaments of superior antennae shorter than peduncle)... P. caramote, auct. b. N o teeth on the under edge. * Three teeth on upper edge, including carapacial crest (no spines on surface of carapace) P. edwardsianus, J. Y. J. ** Nine teeth on upper edge, including carapacial crest (four spines on surface of carapace, two on each side) P. membranaceus, Risso. C. Rostrum equal to carapace in length P. foliaceus, Risso. 3. O n Hyalonema lusitanicum. B y J. S. B O W E R B A N K , LL.D., F.R.S., F.Z.S. &c. On January 24th, 1867, Dr. Gray read a paper at the Zoological Society entitled " Notes on Hyalonema lusitanicum, and on the Genus in general," announcing that Prof. Bocage had presented to the British Museum a specimen of the above-named species. The author adds, " I am enabled to state that I believe it to be a most distinct species from the Hyalonema sieboldii of Japan," or, in other words, from the species he formerly described as H. mirabilis, the structural specific differences said by the author to exist between the two species consisting of differences in the number of spicula in the spiral axis, and their diameter as compared with each other in the respective species; but as these differences in length, number, and diameter of the spicula exist to a very great extent between young and old specimens of II. mirabile, such characters cannot certainly be admitted as specific distinctions. His observations on the size and form of the so-called polypes are equally vague and uncertain ; and the varieties in structure cited may be as readily found in different specimens of H. mirabile as in Prof. Bocage's specimen of H. lusitanicum. There is an aphorism in natural history that no two individuals of the same species are ever exactly alike; and this observation applies with greater force to the protean forms of the Spongiadce than to any other class of animals existing. If the author had but carefully studied the axial columns of the numerous specimens of H. mirabile in his possession, he could not but have rejected such very uncertain characters as those he has adopted. The above are the only organic characters cited by the author in behalf of his opinions ; and he then takes flight into the realms of imagination in support of his purely speculative ideas on the structure and habits of the interesting animal under consideration. Sterne took his hypothetical prisoner and shut him up in a dungeon, and then described all his imaginary woes and sufferings most pathetically; so the Doctor took his Hyalonema, denuded him of |
