1867.] DR. BOWERBANK ON HYALONEMA LUSITANICUM. 901 



A. Rostrum shorter than peduncle of superior antenna 



(six teeth on upper edge) P, sipkonocerus, Phil. 



B. Rostrum longer than peduncle of superior antennje, 



but shorter than carapace. 



a. Teeth on the under edge (filaments of su- 



perior antenna shorter than peduncle)... P. caramote, auct. 



b. No teeth on the under edge. 



* Three teeth on upper edge, including 

 carapacial crest (no spines on sur- 

 face 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, ' 



C. Rostrum equal to carapace in length P. foliaceus, Risso. 



3. On Hyalonema lusitanicum. 

 By J. S. Bo WERE AN 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 lusifanicutn, 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 //. mirahile, 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 dif- 

 ferent specimens of H. mirahile 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 ap- 

 plies with greater force to the protean forms of ttie SpongiadcB than 

 to any other class of animals existing. If the author had but care- 

 fully studied the axial columns of the numerous sp'^cimens 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 inter- 

 esting animal under consideration. 



Sterne took his hypothetical prisoner and shut him up in a dun- 

 geon, and then described all his imaginary woes and sufferings most 

 pathetically j so the Doctor took his Hyalonema, denuded him of 



