314 GINGLYMACONCHA. VENERIDZ. 
STIRPS X. 
Shells somewhat compressed, rather orbicular or orbicularly 
triangular; the umbones nearly central; the cardinal teeth — 
diverging; with a lamella before or behind the cardinal teeth 
in one or both valves. 
Genus 57. CYRACHA. 
Shell orbiculate, triangular, cordiform impression elongate ; 
hinge in one valve with two teeth and lateral lamella; m other 
valve two teeth, and no lateral lamella. Animal unknown. 
i. CYRACHAA SPINIFERA. 
Shells with very many parallel, equidistant lamelle, very 
slightly reflexed, confluescent together in both valves, and ar- 
ranged in a double series of spines; the epidermis yellowish- 
white. Length five-eighths ; height half an inch. 
Venus spinifera, Mont. Test. Brit. 577.—Supp. t. xvu. f. 1; 
M. & R. Trans. Linn. Soc. vii. 78; Flem. Edinb. Encycel. 
vil. 95; Dill. Dese. Cat. 163; Turt. Conch. Dict. 231. 
This species, which is extremely rare, is found only on the 
southern coasts of Devon in deep water, on a sandy bottom. 
Genus 58. CypIppeE. 
The shells orbicular, compressed and thick; no cordiform 
impression ; the right more convex than the left valve; the 
hinge in both valves with two teeth ; the anterior one in the right 
notched, and the lateral lamellee very minute, the left one also 
with two teeth; the anterior one notched, and with more ele- 
vated, thicker Jateral lamelle. 
1. CyprprEe LISTERIANA. 
Shells sculptured with innumerable, concentric, very narrow 
lamellze, the interstices sculptured with very fine elevated lines ; 
