402 MOLLUSCA. 
Figures 587, 587 a. lateral and dorsal views of the shell, enlarged ; 
587 6, the hinge, magnified ; 587, natural size. 
Erycina (Ketiia) quaprata (Gould). 
Testa parva, tenuis, ventricosa, ad angulos rotundata, concentriceé et con- 
cinne striata, epidermide stramineo induta ; umbonibus feré medianis, 
tumidis, anteversis: area cardinalis ampliata, in valva sinistra tri- 
dentata (dente mediano subulato, sub umbone sito ; alteris elongatis, 
compressis) in valua dextra bidentata ; fossd ligamentah triangulart, 
dechvt. 
Erycina (Kellia) quadrata, Gouin ; Proceed. Boston Soc. Nat. Hist., 
ii. 252. June 1850. Expedition Shells, 78. 
SHELL subquadrate, rounded at the angles, thin, nearly equilateral, 
ventricose, the anterior side somewhat less elevated than the poste- 
rior, with obtuse umbonal angles to the disk. Surface very delicately 
grooved concentrically, and covered with a straw-coloured epidermis. 
Beaks central, tumid, turned forwards. Hinge consisting of a shelf 
along the anterior dorsal edge of the left valve, on which are two 
divaricate teeth, sharp and ascendant, the anterior one sweeping off 
along the edge of the shelf; behind the shelf is a triangular sinus, along 
which the cartilage is fixed; there is a posterior lamellar thickening. 
Cardinal tooth wanting in the right valve. 
Length half an inch; height two-fifths of an inch; breadth one- 
fourth of an inch. 
Inhabits the Feejee Islands. (?) 
A very large species of this type, resembling very much Cyclas 
elegans. 
Figures 586, 586 a, lateral and dorsal views of the shell; 586 4, the 
hinge, magnified. 
