314 ZOOLOGY. 



property. The recent animal emits a peculiar odour, 

 which may be compared to that of rotten apples. I 

 have found small pelagic shrimps in the alimentary 

 canal of some examples, and many minute brown 

 crustaceous insects both on the papillae and in the 

 alimentary canal of others. 



Where currents prevail, these creatures are often found 

 collected together in such surprising numbers as to cover 

 a great extent of ocean ; and it is not unusual to observe 

 only their bare internal cartilages, or skeletons, strewn 

 over other tracts of water in great abundance. Sailors 

 account for this latter appearance, on the supposition 

 that the Velellee have been destroyed by the heat of the 

 sun ; but some observations made by my brother, Mr. 

 George Bennett, and published in the " Proceedings of 

 the Zoological Society," prove that the Sea Lizard 

 (Glaucusj feeds on Velella, and that the cleaned 

 skeletons are the result of the depredations of that ex- 

 traordinary little mollusc. 



We obtained specimens of V. Mutica in the Atlantic 

 and Pacific Oceans, from lat, 40 N. to 26 S. 



Another species of Velella, of which we obtained 

 specimens in the Pacific and Indian Oceans, from the 

 Equator to the thirty-sixth degree of south latitude, 

 is smaller than that last described ; and is chiefly 

 remarkable for its internal cartilage possessing a 

 pyramidal or triangular crest, and a more conical base. 

 In other respects its structure is the same as that of 

 V. Mutica. 



PORPITA, SP. 



The genus Porpita is very closely allied to Velella. 

 The internal cartilage is flat and circular, and has no 

 erect crest or sail. Its upper surface is enveloped in a 



