72 Royal Institution. 



A beautiful pinkish yellow species, without .any spots or markings, 

 with the plicse on the fore part undulated and rugulose under the 

 lens. 



Crassatella truncata, A. Adams. C. testa ovata, com- 

 pressa, cornea, pallidiori ad partem anticam, radiis angustis 

 inconspicuis ornata, incequilaterali, latere antico brcviori et 

 rotundato, postico dilatato et truncato, tinea elevata e umbo- 

 nibus ad marginem ventralem ; transversim valde costata, 

 costis acutis subimbricatis. 

 Hab. China Sea, deep water (A. Adams). 



This is a small pale pink or flesh-coloured species, strongly rib- 

 bed, the ribs being sharp, prominent and imbricated ; the posterior 

 side is dilated and truncate, and the surface of the valves is marked 

 with faint linear radiating lines. 



Crassatella compta, A. Adams. C. testa ovato-trigonali, 

 subceqidlaterali, apicibus untrorsum curvatis, rufescenti, trans- 

 verse concentrice plicata ; plicis validis, regu/aribus, subdi- 

 stantibus ; latere antico angustiori, postico latiori, rotundato, 

 interne purpurascente. 

 Hab. China Sea, deep water {A. Adams). 



This is a small red species, with prominent curved beaks, strongly 

 plicate transversely, and of a purplish pink colour in the interior of 

 the valves. 



Crassatella concinna, A. Adams. C. testa ovato-transversa, 

 subcequilaterali, epidermide tenui fusca obtecta, utrinque ro- 

 tundata, concentrice plicata, plicis validis regularibus rvfo- 

 fusco articulatis ; interstitiis creberrime longitudinaliter stria- 

 tis ; umbonibus acutis confertis. 

 Hab. China Sea, deep water (A. Adams). 



A small fuscous species, of an ovate form, rounded at both ends, 

 with the transverse plicae strongly produced and prettily articulated 

 with brownish red. 



ROYAL INSTITUTION OF GREAT BRITAIN. 



May 12, 1854.— Sir Henry Holland, Bart., M.D., F.R.S., Vice- 

 President, in the Chair. 



On the common Plan of Animal Forms. By Thomas Huxley, Esq., 



F.R.S. 



The Lecturer commenced by referring to a short essay by Gee the — 

 the last which proceeded from his pen — containing a critical account 

 of a discussion bearing upon the doctrine of the Unity of Organization 

 of Animals, which had then (1830) just taken place in the French 

 Academy. Gcetbe said that, for him, this controversy was of more 

 importance than the Revolution of July which immediately followed 

 it — a declaration winch might almost be regarded as a prophecy ; for 

 while the Charte and those who establisbed it have vanished as 

 though they had never been, the Doctrine of Unity of Organization 



