MAZATLAN BIVALVES 79 
112, ANOMALOCARDIA suBRUGOSA, Sow. 
Venus subrugosa, Sow. Gen. f.2.—Rve. Conch. Syst. i. pl. 67, 
f. 2.—Hanl. Descr. Cat. p.116:— Wood Suppl. pl. 2, f. 6.— 
Phil. Abbild. Conch. p. 177, pl. 3, f. 6, 7.—Sow. Thes. Conch. 
p. 721, pl. 155, f. 63.—B. WM. Cat. D’Orb. Moll. p. 67, 
no. 595.—C. B. Ad. Pan. Shells, p. 271, no. 440. 
Anomalocardia subrugosa, Desh. B. M. Cat. Ven. p. 116, no. 2. 
=Cytherea subsulcata, Menke, in Phil. Abbild. (ad fid. spec. 
ab ipso accept.) 
This very variable shell is represented on the Atlantic coast 
by A. flexuosa. It is very coarse and heavy ; generally worn 
at the umbos. The earlier part of the shell is covered by 
irregular concentric swellings, which afterwards become eva- 
nescent on the ventral portion, sometimes all over. These are 
crossed by rather deeply cut fine radiating lines, which are 
generally strongest in the depression which marks off the 
posterior beak, rarely becoming punctato-striate. This depres- 
sion however often nearly disappears, and the shell approaches 
A. subimbricata in form. Sometimes it is much flattened, some- 
times remarkably swollen and gibbous ; sometimes very trans- 
verse, sometimes much produced ventrally. The radiating 
grooves sometimes cover the flattened ventral margin, which 
is very finely crenulated within. The lunule is marked by a 
well-defined line, and nearly smooth. The teeth and ligament 
are very strong. Colour generally a yellowish or brownish 
white,’almost always with 2-4 (generally 3) more or less broad 
radiating brown stripes ; and the rest often freckled with dots 
or broken lines. Inside generally with a purple stain about 
the hinge. Epidermis very thin, very pale or brownish. 
A transverse specimen measures long. 1°3, Jat. 1°72, alé. °88. 
An elongated be A BT 7 9 ae mn Bay ho Cae 
A thick 3 43 Reema 7c lhc BSe Wee Maes 
Hab.—Panama, Hanley.—Peru, D’ Orbigny.—Panama ; partly 
buried in coarse sand among stones or under trees, near half 
tide level, rare; C. B. Adams.—S. W. Mexico, P. P. C— 
Mazatlan ; in extreme profusion ; L’pool & Havre Coll. 
Tablet 373 contains 1 minute valve °6 across.—374, 6 young 
specimens, usual state.—375, 6 do. adult.—376, 6 do. more 
beaked.—377, 6 do. more swollen, produced ventrally.—378, 2 
do. shape of A. subimbricata.—379, 6 do. more transverse.— 
380, 3 do. very tumid var. rounded.—381, 6 do. more trans- 
verse.—382, 4 do. beaked.—383, 5 do. flattened var., produced 
