220 TESTACEOUS MOLLUSCA. 
what winged, rather inflated, elliptical, inequilateral, thin: beaks 
scarcely prominent and undulate at tip; cuticle olive somewhat 
shining and striate; nacre white. 14..31.— Near the Rocky 
Mountains. 
A. Pepinrana. Lea. on U.2.p. 96. t. 16. f. 51. Trapezoidal, 
inequilateral, rather inflated, flattened on the sides, thin, transverse, 
carinate anteriorly: beaks prominent: umbonal slope rather 
elevated and rounded : cuticle transversely striated, with the lines 
of growth strongly marked and apparently without rays ; nacre 
white. 11..2.—QOhio.! 
A. Warpiana. Lea. on U. 2. p. 46.¢.14.f. 42. Elliptical 
transverse, thin, somewhat inflated, inequilateral, at the base sub- 
emarginate, dorsal margin curved under the beak : umbonal slope 
rounded : beaks prominent, concentrically undulated at the tip: 
ligament rather short; cuticle green, disposed to be yellow on the 
anterior slope and the beaks : nacre bluish. 1-3, ..3.—Ohio. 
A. Stewartiana. Lea. on U. § in Amer. Phil. Tr. 6. 
Rounded-ovate, very thin, much inflated, anteriorly subangulated, 
posteriorly short and narrower, dorsal line rather short, nearly 
straight and forming obtuse angles at both extremities, ventral edge 
convex ; beaks prominent and granulated at the tip in a short 
double series ; cuticle roughish, olive green, obtusely rayed; nacre 
bluish white, irridescent, sometimes tinged with salmon colour 
about the beaks. 2..3-1,.—Louisiana.2 
A. Granpis. Say. in Transylvania Journal.—A. Corrv- 
LENTA. Cooper. Very large, subovate ; disc unequally wrinkled 
and undulated transversely, dark yellowish brown : umbo elevated; 
beak slightly elevated, with generally two or three small sinuous 
acute undulations ; hinge margin slightly arcuated, sometimes 
nearly rectilinear, somewhat angulated at its anterior termination, 
thence the edge descends by a nearly rectilinear or slightly concave 
Ine to the anterior margin, which is considerably narrowed; sinus 
of the hinge margin concave ; posterior margin widely rounded ; 
within white margined particularly in front, with dusky. 5..73. 
—h. Wabash. 
B. Obovate. 
A. Trapeziauts. Lam. 11.—Ch. f. 762.—£. t. 205. fi 1.— 
Exot. Conch. t. 36. Ovate, fragile, tumid, posterior slope elevated 
compressed and more winged than the anterior, pale yellowish 
olive subradiated posteriorly by darker lines: umbones broad, 


1 Add likewise the A. Cuatziana. Rang. 
* Add likewise the A. Gipposa of Say. 
