Class VL MYA. GAPER. 150 



Sect. II. BIVALVE SHELLS. 



GENUS IV. MYA. GAPER. 



Animal, an Ascidia. 



Shell gaping at one end. 



Hinge, for the most part, furnished with a 

 thick, strong, and broad tooth, not in- 

 serted into the opposite valve. 



M.Truncata. Lin. Syst. 1112. List. Angl. tab. v-jig. 36. 1# TRUN . 



Gm. Lin. 3217. Faun. Suec. Lin. Tr. viii. 35. cata. 



No. 2126. Mont. Test. Br. 32. abrupt. 



M. with a broad, upright, blunt tooth, in one 

 shell; the closed end rounded; the open end 

 truncated, and gaping greatly ; the outside yel- 

 low, marked with concentric wrinkles; length 

 an inch and an half, breadth three inches. 

 Tab. xliv. 



Lodged under muddy ground, near low-water 

 mark ; discovered by an aperture in the slime, 

 beneath which it is found in coarse gravel. 



