M. Valenciennes on the Organization of Lucina and Corbis. 43 



phalous moUusk occurs, whose elegant shell, for a long time rare 

 and consequently sought for in collections, is well-known. Lin- 

 naeus called it Venus Corbis; Lamarck arranged it among the 

 Lucina. Cuvier founded a genus with this species which pre- 

 sents indeed very striking characters ; he left it near Lucina, as 

 Lamarck had previously done. I have been so fortunate as to 

 meet with an animal of this species in a state of excellent pre- 

 servation among the collections made at the Friendly Islands by 

 M. Quoy, and which that zoologist has not had time to study; 

 at least he has not spoken of it in the account of the voyage of 

 the Astrolabe. This moUusk has likewise only a single branchia 

 on each side of the visceral mass, and I have confirmed this same 

 conformation on a second individual brought from the Feejee 

 Islands. However, the structure of its non-perforated foot di- 

 stinguishes it from the animals of Lucina. 



From a sole comparison of the shells, it was thought that the 

 Ungulince offered some relations with the Lucince. We are ac- 

 quainted with the moUusk of this genus from the excellent 

 anatomical descriptions made and published by M. Duvernoy. 

 As this anatomist found four branchial laminse, it is impossible 

 any longer to admit of an approximation between the Ungulince 

 and the Lucina. My investigations confirm the relations pointed 

 out between the Ungulince and Mytilacea. 



It results, therefore, from the observation made by me, that 

 the Lucina and Corbis differ from all the Acephalous Mollusca by 

 a very prominent character, viz. that they possess only a single 

 branchia on each side of the foot and viscera. 



Since I have confirmed this fact on animals inhabiting the 

 Mediterranean, the coasts of Africa, the Antilles, as well as the 

 seas of Brazil and of the Indies, we are led to admit it as a ge- 

 neral fact in the animals of this family ; it cannot be regarded as 

 a simple exception, which might have been the case had it been 

 observed only on a single individual or on a single species of 

 Lucina. 



This great exception is not the only one which the Lucina 

 present : the aperture of the mouth is very small, surroimded by 

 two weak and thin folds of the skin, which require the greatest 

 attention to be seen ; they are the rudiments of lips. 



But what is most remarkable is, that the labial palpi are all 

 four wanting. There may possibly be traces of them in the 

 animal of Corbis. 



Poli has given a very excellent figure of his Loripes, or of 

 Lucina lactea. It will be seen from it that he was entirely pre- 

 occupied in his investigation with the singularity of the foot of 

 the animal, for he has represented the branchiae situated to the 

 right and left of the viscera, without noticing the very remark- 

 able exception in the number of the laminge. As M. Cuvier has 



