70 
Vl-l)RSCKMPTl()N 0}^ (JPNU8 AND SPEC[ES. 
Genus— DESMA, Morris. 
TsOCardia, .7. de C. Sowerby, ^Mitchell’s Three Exped. Int. E. Austr., 1838, I, p. 15. 
Ennjdesina , Morris, Strzelecki’s Phys. Descript. N. S. Wales, &c., 1845, p. 274. 
,, Dana, Wilkes’ U.S. Explor.*Exped., X (Geol.), 1849, p. 699. 
,, Stoliczka, Cret. Fauna S. India (Pal. Tndica), 1871, III (Pelecypoda), Pt.5, p. 226. 
Waajven, Salt Pange Fo^^sils (Pal. Indica), 1891, IV, Pt. 2, p. 137. 
Tjeiomy^dina, Freeh, Abhandl. Specialkarte, Preuss. Thiiring. Staaten, IX, Heft 3, 1891, p. 201. 
,, Freeh, Poemer’s Lethaja Pal., II, Lief. 3, 1901, p. 600. 
Generic Characters . — Shell Inrge, heavy, obliquely cordate or oval; 
iuequi valve; very inequilateral. Valves convex, usually ventricose, much 
thickened in the uiuhonal I'eg’iou ; cardinal margin much arched; umhones 
]u-omineut, prosogyi ate, incurved, and acute. Ligament absent, resilium 
well d(ivel()|)ed, opisthodetic ; resilifer transversely elongate, concave; a 
promineiit cardinal fold rising from the ventral margin of the hinge-plate, 
and in a vt'rtical line with the umhonal a[)ex, present in both valves, the fold 
in the right valve fitting under that in the left. Lunule large, cordate, and 
deep. Adductor scar la’ge, faint, and little impressed ; mantle retractor 
scars well mai'ked, ])it-like, and arranged in a Z-shaped line from posterior 
to anterior; pallial imjrres^ion very faint, continuous. Structure of test 
laminar. 
Type — Eu yftc.'-ma cord at am, Morris 
