134 CYCLAS. 



CIJLTELLUS. Schum. 1817. Ex. L. Solenoides. PI. iii. fig. 78. 



CUMA. Humph. Part of I'usus and Pasciolaeia, Lam. 



CUMINGIA. Sowerby, 1833. Fam. Mactracea, Jj&m.—Bescr, 

 Equivalve, inequilateral, transverse, rounded anteriorly, sub- 

 rostrated posteriorly. Hinge with a central spoon-shaped cavity 

 in each valve, containing the cartilage ; a very small anterior 

 cardinal tooth in each valve ; two lateral teeth in one valve, none 

 in the other : muscular impressions two in each valve, distant ; 

 palleal impression with a very large posterior sinus. — Obs. The 

 species known at present are found in sand, in the fissures of 

 rocks in Tropical climates. They resemble Erycina in general 

 form and character, but difier in having the internal cartilage 

 placed in a prominent spoon-shaped process, while that of 

 Erycina is contained in a hollow which sinks under the umbones. 

 This genus should be placed near Amphidesma. Cumingia 

 mutica. PL iv. fig, 87. 



CUISrEIPOEM. (Cuneus, a wedge.) "Wedge-shaped, as Donax, 

 fig. 108. 



CUNEUS. Megerle, 1811. Merge, Schumacher, 1817. PL vi. 

 fig. 117. a. 



CUEVED. Arched or bent. Ex. Dentalium, fig. 2. 



CUVIEEIA. Eang. 1827. (Baron Cuvier.) Class, Pteropoda, 

 Lam. — Bescr. Thin, transparent, glassy, cylindrical, rounded 

 and inflated at the closed extremity, compressed towards the 

 opening, so as to render it oval. This genus differs from Yagi- 

 nula in being rounded, instead of pointed, at the lower extremity. 

 Mediterranean. C. Columella. PL xii. fig. 223. 



CYCLAS. Brug. Fam. Conques Eluviatiles, Lam. Conchacea, 

 Bl. — Bescr. Orbicular, thin, subovate,ventricose, sub-equilateral, 

 equivalve ; cardinal teeth minute, one more or less complicated 

 in the left valve, two diverging in the right ; lateral teeth 

 elongated, compressed, laminar, acute doubled in the left valve ; 

 ligament external ; epidermis thin, horny. — Obs. The Cyclades 

 are viviparous, and abound in ditches, ponds, slow streams, &c. 

 in Europe and North America. The genus Pisidium has been 

 separated on account of a difference in the animal, and may be 



