M. Valenciennes on the Organization of Lucina and Corbis. 43 
phalous mollusk occurs, whose elegant shell, for a long time rare 
and consequently sought for in collections, is well-known. Lin- 
neus called it Venus Corbis; Lamarck arranged it among the 
Lucine. Cuvier founded a genus with this species which pre- 
sents indeed very striking characters; he left it near Lweina, 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 mollusk has likewise only a single branchia 
on each side of the visceral mass, and I have confirmed this same 
conformation on a second idividual brought from the Feejee 
Islands. However, the structure of its non-perforated foot di- 
stinguishes it from the animals of Lweina. 
From a sole comparison of the shells, it was thought that the 
Unguline offered some relations with the Lucine. We are ac- 
quainted with the mollusk of this genus from the excellent 
anatomical descriptions made and published by M. Duvernoy. 
As this anatomist found four branchial lamine, it is impossible 
any longer to admit of an approximation between the Unguline 
and the Lucine. My investigations confirm the relations poimted 
out between the Unguline and Mytilacea. 
It results, therefore, from the observation made by me, that 
the Lucine and Corbis differ from all the Acephalous Mollusea 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 
Enicina. 
This great exception is not the’ only one which the Lucine 
present: the aperture of the mouth is very small, surrounded by 
tivo 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 
Eucina lactea. Yt 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 branchie situated to the 
right ‘and left of the viscera, without noticing the very remark- 
able exception in the number of the lamine. As M. Cuvier has 
