MAZATLAN BIVALVES 79 



112. Anomalocaedia stjbettgosa, Soto. 



Venus subrugosa, Soto. Gen. f. 2.—Rve. Conch. Si/st. i. pi. 67, 

 f. 2.—Sanl. Bescr. Cat. p. 116 -.— Wood Suppl. pi. 2, f. 6.— 

 Phil. Ahbilcl. Conch, p. 177, pi. 3, f. 6, 7.—Soii\ Thes. Conch. 

 p. 721, pi. 155, f. m.—B. M. 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. 

 = Cytlierea subsulcata, Menke, in Phil. Ahhild. (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 oyer. 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 xmnctato-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 

 weH-defined Une, 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 Avith dots 

 or broken lines. Inside generally with a purple stain about 

 the hinge. Epidermis very thin, very pale or brownish. 

 A transverse specimen measures teg'. 1 ■ 3, lat. 1' 72, alt. "88. 

 An elongated „ „ „ l'4f9, „ 1*78, ,, 1. 



A thick „ » „ 1-48, ., 1-88, „ 1-2. 



HaZ>.— Panama, Hanley.— Peru, D'Orbigny.— 'Panama; partly 

 buried in coarse sand among stones or under ti-ees, near half 

 tide level, rare ; C. B. Ada77is.—S. W. Mexico, P. P. C— 

 Mazatlan ; in extreme profusion ; L'pool Sf 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- 

 yerse.— 382, 4 do. beaked.— 383, 5 do. flattened var., produced 



