110 MYA. 



KNOBBED GAPER. 



34. Mya nodosa. M. testa ovali, tenera, virescente, natibus nodulosis. 

 Linn. Gmel. p. 3222. 



Shell oval, thin, greenish ; umbones knobby. 

 Chemn. Conch. 10. pi. 170. f. 1650. 



This is a green, fresh-water shell, smooth in every 

 part, except near the hinge, where a few knobs, or pro- 

 tuberances, appear. Its country is not mentioned. 



SPURIOUS GAPER. 



35. Mya spuria. M. testa rhombea, viridi ; umbonibus glabris. Linn. 

 Gmel. p. 3222. 



Shell rhombic, green ; umbones smooth. 



Schrot. Conch. 2. pi. 7. f. 5. Favanne Conch, t. 62. f. 11. Encyclop. 

 Method, pi. 249. f. 3. 



This is a green shell, resembling in shape the M. 

 corrugata, but is nearly twice as large, and smooth 

 about the hinge. We have Schroter's authority for its 

 specific distinction. It inhabits the rivers of Tran- 

 quebar. 



ANGULAR GAPER. 



36. Mya syrmatophora. M. testa ovata, depressa ; cardinis marginc ad 

 dentem primarium mucrone subulato, altero dilatato. Linn. Gmel. 

 p. 3222. 



Shell oval, depressed ; margin of the hinge with an-awl shaped projec- 

 tion near the primary tooth, that of the other valve dilated. 

 Gron. Zooph. pi. 18. f. 1. 2. 



This species is about two inches and a quarter long, 

 and two inches broad. Gronovius describes it as 

 having marginal teeth on each side, with parallel du- 

 plicatures. It is nearly of a triangular shape. In- 

 habits the rivers of Guinea. 



