150 AMERICAN MARINE CONCHOLOGY. 



A doubtful species, of which only one specimen was received by 

 Mr. Say. 



8. T. decora, Say. Figs. 358, 359. 



Journ. Philad. Acad., v. 219. 1826. 

 Transversely subovate, not much compressed, with numerous 

 minute concentric wrinkles and regular equidistant lines crossing 

 them ; no oblique lines on the posterior margin. Anterior lateral 

 tooth of the left valve prominent, the others obsolete ; apex a little 

 before the middle. Rosaceous, or white with rosaceous radiations. 

 Length 22, height 19 mill. 



Southern Coast. 



9. T. lateralis, Say. 



Journ, Philad. Acad., v. 218. 1826. 



Shell transversely subovate ; beaks nearly central. Anterior 

 margin regularly rounded ; posterior margin rostrated, the beak 

 turning to the left and slightly gaping ; ligament slope straight ; 

 basal margin regularly arcuated. Valves with small concentric 

 wrinkles and slight waves ; within, these are slightly impressed. 

 Lateral teeth none ; cardinal teeth two in one valve, and one, with 

 another scarcely elevated filiform tooth in the other. Whitish, 

 often tinged with rusty; within white. 



Length 52, height 3? mill. 



SoutJiern Coast. 



I am not acquainted with this species. 



10. T. lusoria, Say. Fig. 360. 



(Psammobia.) Journ. Philad. Acad., ii. 304. 1822. 

 Shell oblong, suboval, with minute wrinkles ; posterior side 

 narrowed, and inclining to the right at the end ; an obtuse convex 

 line on the left valve. Bluish-white. 

 Length 1, height .6 inch. 



New Jersey to Florida. 



Doubtful Species. 



11. T. versicolor, Cozzens. Fig. 361. 



DeKay, Moll. N. Y. 209, t. 20, f. 272. 1843. 

 Shell transverse, compressed, inequilateral, slightly gaping at 

 its subacute extremity, smooth, posterior end subangular, with 

 an indistinct fold ; anterior extremity dilated and rounded. Car- 

 dinal teeth two in the right valve; the posterior more robust, 

 simple, in the left valve rudimentary or inconspicuous. White, 



