86 KELLIADiE. 



compared with that presented by Kellia suborhicularis, viz., 

 the open anterior tube of the former, as contrasted with the 

 closed one in the latter, that we were almost inclined to 

 adopt Poronia in a new sense. But in one of the lately- 

 published numbers of the " Mollusques d'Algerie " there 

 is a beautiful figure of the animal of Eryc'ina Geoffroyi^ 

 an undoubted Kellia as to its shell, presenting the very 

 conformation observed by Mr. Alder in the rubra, whilst 

 on the other hand, a figure of the Bornia seminulum of 

 Philippi, identical specifically with the rubra, represents 

 the anterior process as a true tube ; in this respect agree- 

 ing with a drawing and description of the animal of rubra, 

 communicated to us by Mr. Clark. These facts induce us 

 to conclude, that the peculiar conformation of the hyaline 

 anterior process, whether tube or canal, is probably an in- 

 dividual, and possibly a sexual difference. At any rate, in 

 the present state of the case, it cannot be received as 

 generic. We need scarcely say, that the animal of the 

 Poron, as quoted by Recluz from Adanson, does not in the 

 least agree with that of any of our Kellia. Chironia of 

 Deshayes and Cydadina of Cantraine appear to be syno- 

 nymous groups. 



The Kelli(E are small, but elegant, bivalves, living 

 usually in crevices of rocks, or shells, or sea-weeds, spinning 

 a byssus, or lying free. They bear a striking external 

 resemblance to the fresh water Cyclades. Some live along 

 the coast line, others in the depths of the ocean. They 

 have been included in the heterogeneous genus Erycina, 

 founded by Lamarck, for a sti-ange mekinge of Tellina, 

 Dlplodonta, Astartes and Kellict, but 2:)roposed recently by 

 M. Recluz to be restricted to an assemblage including 

 Kellia; proper and Moniacuta. The name, however, with 

 all the confusion which attends it, had far better be 



