100 CAKOCOLLITS. 



cardinal teeth, two in each valve, locked into each other cross- 

 wise, lateral teeth, two in each valve, remote ; muscular im- 

 pressions, two in each valve ; palleal impression entire. Liga- 

 ment external, inflated. — Obs. Although this genus includes 

 many remarkable forms, the characters are so easily defined that 

 there is no difiiculty in distinguishing it from any other genus. 

 The principal forms are Cardium Angulatum, fig. 123, and 

 C. Hemicardium, fig. 123** ; Cardium Grcenlandicum, fig. 123*. 

 (Apheodite) Cardium Dionseum, fig. 122, (Cardissa) and 

 Apertum, fig. 503, 4. (Papyridea.) PI. vi. It is somewhat sur- 

 prising that this genus, which contains some of the most beau- 

 tiful forms of bivalve Testacea, shoidd have been left till quite 

 lately without any attempt to revise the species and settle the 

 synonyms. The monograph in the Author's Conchological Illus- 

 trations contains sixty species from all climates. PI. vi. fig. 122, 

 123, 123*, 123**. PI. xxiv. fig. 503, 504. 



CAEINAEIA. Lamarck, 1801, Class, Cephalopoda. Division, 

 Monothalamia, Lam. Fam. Nectopoda, Bl. — Descr. Symmetri- 

 cal or nearly so, conical, thin, glassy, fragile, patelliform ; with 

 a fimbriated dorsal keel; apex convolute, bent forwards ; aper- 

 ture oval, pointed at the dorsal extremity. Hab, Amboyna, 

 Indian Ocean, and Mediterranean Sea. — Obs. A most singular 

 and beautiful shell, remarkable for its transparency, its fragile 

 structure, arid the dorsal keel, whence it derives its name. It 

 was once so rare that a single specimen of the large species 

 realized a hundred guineas. C. Mediterranea. PI. xxiii. fig. 488. 



CAEINATED. (From Carina, a keel.) Applied to any shell 

 having a raised, thin ledge, passing roimd a whorl or any other 

 part of a shell, as in Carinaria, fig. 488. 



CAEINEA. Swainson, 1840. Ultimus, Montf. 1810. Ovultjm 

 gibbosum, Auct. fig. 343, and similar species. 



CAB-INELLA. Adanson. Luteaeia papyracea. Lam. Fam. 

 Mactracea, Lam. Fig. 77. 



CAHINIDEA. Swainson, 1840. iNruNDiBULUM. Montf. 1810. 



CAEOCOLLUS. Montf. Fam. Colimacea, Lam.- 2)e*rr. Orbi- 

 cular, depressed, v.ith the outer side of the whorls angulated or 



