CURVULA. 129 



bones 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. — Obs. This 

 genus very much resembles Area in general form, but differs in 

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

 singularly prominent edge of the muscular impression. China. 

 Fig. 133, C. Auriculifera. 



CUCUMIS. Klein. Marginella, Auct. 



CULTELLUS. Species of Lutraria, Lam. which have the urn- 

 bones placed near the extremity of the shell. Ex. L. Solenoides, 

 fig. 7S. 



CUMA. Humph. Fusus and Fasciolaria, Lam. 



CUMINGIA, Sow. Fam. Mactracea, Lam. — Descr. Equivalve, in- 

 equilateral, transverse, rounded anteriorly, subrostrated posteriorly. 

 Hinge with a central spoon- shaped cavity in each valve, contain- 

 ing 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 differ 

 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, fig. 87. 



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

 fig. 108. 



CUNEUS. Megerle. Venus Meroe, Linn, and similar species. 



CUNICULA. Sw. A sub-genus of Uniones, thus described : — 

 " Ovate, oblong; bosses thick, but depressed; cardinal teeth mode- 

 rate. C. planulata, patula, rubiginosa, secura, purpurascens." 



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



CURVULA. Rafinesque. A fossil imperfectly described as dif- 

 fering from Pinna, in being inequivalve. 



