20 TESTACEOUS MOLLUSCA. 
composed of a rounded tooth which projects forward, and a smaller 
acute one by the side of it. 3..53.—N. Murope 
M. Cancetuata. Conr. Jour. A. N.S. Phil. 7. p. 236. t. 18. 
f. 2. Subelliptical, ventricose, with numerous prominent slightly 
undulated concentric strie ; a slight furrow extends from beak to base, 
posterior side with radiating strie, umbo prominent, anterior side 
short: tooth very erect, dilated, biemarginate. +.. 2.—U. California. 
M. Semistriata. Nobis in Zool. Pr. 1843. Ovate-oblong, sub- 
equilateral, tumid, posterforly rounded, anteriorly attenuated ven- 
trally and subtruncated at the extremity; white, thin, pellucid ; pos- 
terior area smooth, the central with crowded fine radiating strize 
which anteriorly become fine ribs and terminate at the anterior slope 
which is roughened by transverse sublamellar wrinkles: tooth resem- 
bling that of Arenaria but more oblique. 3..1.—J have seen but 
one valve. 
ANATINA. 
Transverse, subequivalve, gaping at one or both ends. Primary 
tooth naked, dilated, spoon-shaped, somewhat projecting internally 
and receiving the ligament in each valve. In many species, an 
affixed lamina or false rib runs obliquely under the cardinal 
teeth. 
A. Lanterna. Lam. 1.—Born. p. 23. vignette 6.—Soren Spen- 
gleri, W. t. 3. f. 30. Ovate, rounded at each extremity, and not 
beaked anteriorly ; very thin, fragile, swollen, pellucid and white. 
1..2.—Indian Ocean. 
A. Truncata. Lam. 2. (partly )—Del. t. 3. f. 2. Ovate, thin, 
white, transversely striated, anteriorly subtruncated, roughened by 
minute raised dots: subnacreous within.— China. ? 
A. Susprostrata. Lam. 3.—SoLen Anatinus. Lin. Gmel. no. 
8.—D. p. 65.—Ch. f. 46, 48.—H. t. 228. f. 3.—W. t. 3. f. 13. 
Ovate, membranaceous, pellucid, white and very thin gibbous, a very 
short minute radiating fissure at the beaks: anterior end gaping 
the more widely and subrostrated. 1}..2.—Indian Ocean and 
New Holland. 
A. Gurospunosa. Lam. 5.—Mya Anatina, Gmel. 3221.—D. p. 
44.—Ch. f. 13 to 16.—W. t. 2. f. 6. Subglobose, the anterior 
side very short and gaping, hiatus with a marginated border ; thin 
but firm, decussated, white and pellucid. 1.— Africa. 
A. TrarezorwEs. Lam 6.—H.t. 230. f. 6.—OsvropesMa T. 
Bl. t. 76. f. 8. Rounded-trapeziform, one side very short and 
truncated, the other rounded; slightly imequivalve, convex, thin, 

1 Mya Erodona, Lam. 3, is a Corbula. Mya Solemyalis belongs 
to OsTEODOMA. 
