TELLINIDJB. 165 



three cardinal teeth in one and two in the other valve ; all bifid ; 

 no lateral teeth, pallial sinus deep. 



COOPERELLA, Carpenter. Cartilage snbinternal, 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, 



CuMiNGiA, Sowb., 1833. 



Dedicated to Hugh Cuming, a very distinguished collector of 

 shells ; his cabinet now belongs to the British Museum. 



Distr. — 10 sp. In sponges, sand, and the fissures of rocks; 

 7 fathoms. W. Indies, India, Australia, West America. Fossil. 

 Miocene — ; Wilmington, North Carolina. G. mutica, Sowb. 

 (ex, 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. 



MoNTROUZiERA, Souvcrb., 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. 31. clathrata, 

 Souverb. (cxi, 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, 1866. 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 valve a single one bifid ; no lateral teeth. Th. pulchra^ 

 from Singapore, is the only species as yet known. 



Family TELLINID^. 



Shell free, compressed, usually closed and equivalve ; cardinal 

 teeth 2 at most, laterals 1 — 1, sometimes obsolete; muscular 

 impressions rounded, polished ; pallial sinus very large ; liga- 

 ment on shortest side of the shell, external. Structure obscurel}^ 

 prismatic-cellular ; prisms fusiform, nearl}'- parallel with surface, 

 radiating from the hinge in the outer layer, transverse in the 

 inner. 



