[541 ] '^^ 



^ LXV. Proceedings of Learned Societies. 



^ ROYAL SOCIETY. 



[Continued from p. 323.] 



April 6, 1854.--Thomas Graham, Esq., V.P., in the Chair. 



''TPHE following paper was read: — ''On a peculiar Arrangement 

 -* of the Sanguiferous System in Terehratula and certain other 

 Brachiopoda." By W. B. Carpenter, M.D., F.R.S. 



In a memoir " On the Minute Structure of Shell," read before the 

 Royal Society January 17, 1843, (and subsequently embodied in a 

 " Report " on the same subject, prepared at the request of the 

 British Association for the Advancement of Science, and published 

 in its Transactions for 1844,) I first announced the fact, that the 

 * punctations ' which had been previously noticed on the exterior 

 of many Brachiopodous shells, both recent and fossil, are really the 

 orifices of tubular perforations, which pass directly through each 

 valve, from one of its surfaces to the other (fig. 1). 



Having subsequently obtained specimens of Terehratula in which 

 the soft parts of the animals had been preserved, in connexion with 

 their shells, I ascertained that these passages are occupied in the 

 living state by membranous caeca, closed externally, but opening on 

 the internal surface of the shell, and filled with minute cells of a 

 brownish hue. Recollecting that Professor Owen, in his account of 

 dissections of some species of Terehratula and Orhicula (Transac- 

 tions of the Zoological Society, vol. i.), had spoken of an unusual 

 adhesion of the mantle to the shell in these Bivalves, it occurred to 

 me that this adhesion might be due to a continuity between the 

 mantle and these csecal tubuli ; and I carefully sought for evidence 

 of such a structure. In this, however, I was entirely unsuccess- 

 ful ; for the mantle, when stripped from the shell, presented no ap- 

 pearance whatever of having transmitted any such prolongations 

 into its substance ; on the contrary, it was evidently continued over 

 the mouths of the cseca with which it was in apposition ; and I fre- 

 quently found its external surface (that in contact with the shell) 

 covered in patches with cells exactly resembling in size and aspect 

 those contained within the caeca. I was equally unsuccessful in the 

 attempt to trace any other connexion between these caeca and the 

 soft parts of the animal ; so that, although their importance in its 

 oeconomy scarcely admitted of doubt, the nature of their function re- 

 mained entirely unknown^ The idea that they had any connexion 

 with the formation of the shell itself, seemed to be completely nega- 

 tived by the fact, that in a large proportion of the group of Brachio- 

 poda, no such perforations exist ; notwithstanding that their shells, 

 in every other feature of minute structure, are exactly accordant 

 with that of Terehratula. — The foregoing results were communicated 

 to the British Scientific Association in 1847, and were embodied in 

 the Second Part of my " Report " published in its Transactions for 

 that year. 



The physiological importance of the characters of ' perforation ' 



