36 
CYRENA. 
CYPRAECAS'SIS. Stutch. (Cypreea and Cassis.) Deser. Sheli, 
when young, striated, reticulated or tuberculated; outer-lip 
simple: when mature, outer-lip involute and toothed; colum- 
ellar lip also toothed; aperture straight, anteriorly terminated 
by a recurved canal, posteriorly by a shallow channel. Animal 
with the mantle bilobed; operculum none. Obs. The reasons 
given for separating this genus from Cassis, are, Ist, That the 
shells of the latter have an operculum, while those of the proposed 
genus has none. 2nd, That the Cyprecassides do not form a 
complete, thickened lip, before the full period of their growth, 
like the Cassides. 3rd, That the Cypracassides have no epi- 
dermis. The species mentioned as probably belonging to 
Cyprecassis are C. rufa, the type; C. Coarctata, and C. Tes- 
ticulus, Auct. The establishment of this genus has been opposed 
on the ground that indications of epidermis are discoverable in 
some specimens of C. rufa; that some specimens of the same 
species and Testiculus have been examined, and found to have 
formed slightly thickened and denticulated outer-lips at very 
early periods of growth, while many of the other Cassides are 
destitute of varices, and that an operculum of C. coarctata was 
brought to this country by Mr. Cuming. It is probable, how- 
ever, that an increased knowledge of facts might go far to 
establish the propriety of the separation. C. Testiculus, fig. 412. 
CYPRASO’'VULA. A genus of Cyprzidze thus described: “Shell 
like cowry, but front end of columella covered with regular cross- 
ribs, like rest of base, internally produced into an acute toothed 
ridge. Shell pear-shaped, cross-ribbed.”’ C. Capensis. 
CYPRICAR’DIA. Lam. Fam. Cardiacea, Lam. Deser. Equi- 
valve, inequilateral, sub-quadrate, transversely elongated, with 
the anterior side very short. Hinge with three cardinal 
teeth and one posterior, elongated, remote lateral tooth in each 
valve. Muscular impressions two in each valve; ligament 
external. Obs. This genus is distinguished from Cardita by 
the three cardinal teeth. Cypricardia is Marine. Fig. 125, 
C. Angulata. 
CYPRINA. Lam. Fam. Conques Marines, Lam. Conchacea, 
Bl. Deser. equivalve, inequilateral, sub-orbicular; umbones 
curved obliquely; hinge with three diverging cardinal and one 
remote lateral tooth in each valve. Ligament external. 
Muscular impressions two in eace valve; palleal impression 
having a slight posterior sinus. Epidermis thick, rough, brown. 
Obs. The Cyprine belong to the Northern hemisphere. 
The recent species are not numerous. Fossil species are found 
in the tertiary deposits. Cyprina may be known from Venus by 
the remote lateral tooth and the thick epidermis. Fig. 116, 
C. vulgaris. 
CYRE'NA. Fam. Conques Fluviatiles, Lam. Conchacea, BI. 
