CONCHIFERA. 467 
Synonyms, Glossus, Poli; Bucardium, Muhlfeldt; Pecchiol.a, 
Meneghini. 
Shell cordate, yventricose; umbones distant, sub-spiral; 
ligament external; hinge-teeth 2.2 ; laterals 1—1 in each valve, 
the anterior sometimes obsolete. 
Animal with the mantle open in front; foot triangular, 
pointed, compressed; siphonal orifices close together, fringed ; 
palpi long and narrow; gills very large, nearly equal. 
Fig. 260 J/socardta cor. 
The heart-cockle burrows in sand, by means of its foot (/) 
leaying only the siphonal openings exposed. (Bulwer.) 
Distribution, 5 species. Britain, Mediterranean, China, Japan 
Fossil, 90 species. Trias —. United States, Hurope, South 
India. 
The Isocardia-shaped fossils of the old rocks belong to the 
genera Cardiomorpha and Jso-arca; many of those in the 
Oolites to Ceromya. Casts of true Isocardie have only two 
transverse dental folds between the beaks, and no longitudinal 
furrows. 
CYPRICGARDIA, Lamarck. 
Example, C. obesa, Pl. XX., Fig. 4. C. rostrata, Fig. 261. 
Synonyms, Trapezium, Humph. Libitina, Sch. 
Shell oblong, with an oblique posterior ridge; umbones 
anterior depressed; ligament external, in deep and narrow 
grooves; cardinal teeth 2.2, laterals 1—1 in each valve, some- 
times obscure; muscular impressions oval (of two elements); 
palhal line simple. 
