TELLINIDZ. 165 
three cardinal teeth in one and two in the other valve; all bifid ; 
no lateral teeth, pallial sinus deep. 
COOPERELLA, Carpenter. Cartilage subinternal, the ligament 
contiguous to it, the cardinal teeth lamellar, simple or one of 
them bifid. This subgenus is perhaps allied to Metis, H. and 
A. Adams. 
CumrinaiaA, Sowb., 1833. 
Dedicated to Hugh Cuming, a very distinguished colleetor of 
shells ; his cabinet now belongs to the British Museum. 
Distr.—10 sp. In sponges, sand, and the fissures of rocks ; 
T fathoms. W. Indies, India, Australia, West America. Fossil. 
Miocene—; Wilmington, North Carolina. C. mutica, Sowb. 
(cx, 40). 
Shell transversely oval, equivalve, rounded in front, subros- 
trated and slightly gaping behind, small, thin, often irregular in 
form; hinge with a spoon-shaped cartilage-pit, and a small ante- 
rior cardinal tooth in each valve; two elongated lateral teeth in 
the right valve, less developed in the left; beaks small; surface 
concentrically ridged ; pallial sinus very wide. 
MonrrovuziERa, Souverb., 1863. 
Dedicated to a French conchologist resident in New Cale. 
donia, and who has greatly contributed towards a knowledge of 
its shell-fauna. 
Distr.—2 sp. New Caledonia, Mauritius. Jf. clathrata, 
Souverb. (exi, 43-45). 
Shell moderately elongated, hinge with the cartilage in a pos- 
teriorly directed groove, two cardinal teeth in front of it in the 
right valve, a single triangular, bifid one in the left; posterior, 
but quite close to the cartilage-pit, there is in each valve one 
short lateral tooth, looking, however, more like a posterior car- 
dinal. 
THYELLA, H. and A. Adams, 1865. Shell rather inflated, sub- 
triangular, truncated posteriorly, surface decussated, striated ; 
cartilage in an almost straight, projecting process; hinge in the 
right valve with two cardinal teeth, of which the anterior is bifid; 
in the left vaive a single one bifid ; no lateral teeth. Th. pulchra, 
from Singapore, is the only species as yet known. 
Famity TELLINID &#. 
Shell free, compressed, usually closed and Satta lte ; cardinal 
teeth 2 at most, laterals muscular 
impressions rounded, polished; pallial sinus very large ; liga- 
ment on shortest side of the shell, external. Structure obscurely 
prismatic-cellular ; prisms fusiform, nearly parallel with surface, 
radiating from the hinge in the outer layer, transverse in the 
inner. 
