CUCUMIS. 



133 



Ceplialophora, Bl. containing families of molluscous animals 

 destitute of shells. 



CETPTODON. Turton, 1822. A genus of Lucinseform shells, 

 differing from that genus in the character of the hinge and pal- 

 leal impressions, and having a fold at the posterior side of the 

 shell. Partially described by J. Sowerby, under the name 

 Axinus, and named Thyatira, besides several other names by 

 Leach. C. Sinuosum. PI. sxvii. fig. 575. 



CETPTOPTHALMUS. Ehrenherg. A sub-genus of BulHdae, 

 the shells of vs^hich are thus described in Adams's Monograph, 

 No. 11 Sowerby' s Thesaurus : " Shell fragile, horny, scarcely 

 involute, destitute of columella and spire ; aperture wide." 



CETPTOSTOMA. Bl. 1825. Difiers from Sigabettjs, Lam. 

 principally in the soft parts of the animal. De Blainville re- 

 marks that he is acquainted with only two species (from the 

 Indies), which he can with decision refer to the genus, but he 

 thinks that many of the Lamarckian Sigareti may very properly 

 be found to belong to it, as soon as the soft parts shall be known. 

 The species which he figures is Cryptostoma Leachii. (Manuel 

 de Malacologie, pi. xlii. fig. 3.) 



CTENO CONCHA. G-ray. Described as having many characters 

 common with the Solens, the teeth like ISTucuIa, but the cartilage 

 entirely external. Solenella, Sow. ? 



CirCTJLLJEA. Lamarck, 1801. (CucuUus, a hood.) Fam. Ar- 

 cacea, Lam. — Descr. Sub-quadrate, nearly equivalve, sub-equi- 

 lateral, deep ; hinge rectilinear, with a series of angular teeth, 

 small near the umbones ; larger and more oblique towards the 

 extremities ; umbones separated by a flat external area, on which 

 the ligament is spread. Anterior muscular impression produced 

 into a sharp-edged plate or ledge, projecting from the side of the 

 shell. Posterior muscular impression flat and indistinct. — 06*. 

 This genus very much resembles Area ia general form, but 

 differs in the oblique, lengthened character of the remote teeth, 

 and in the singularly prominent edge of the muscular impres- 

 sion. Chiaa. C. Auriculifera. PI. vu. fig. 133. 



CUCUMIS. Klein. Maegpenella, Auct. 



