DIMYARIA. 161 



Anatbia dedans. — The Sloping Anatina. Plate 

 XVIII. fig. 5. Oval, thin, brittle, a little gaping near the 

 end, where it is truncated, slightly wrinkled concentrically ; 

 yellow sand-colour. Two inches broad. Inhabits the 

 British seas. 



Genus 58 MY A. — Linnceus. 



Generic Character Transverse, gaping at both ends, 



with one large dilated projecting and nearly vertical primary 

 tooth in the left valve, and with a hollow in the opposite 

 valve; ligament internal, short, thick, and inserted in the 

 hollow of the primary tooth on the one side, and in the pit 

 of the other valve. 



Mya truncata. — The Truncated ]\Iya. Plate XVIII. 

 fig. 6. Suboval, truncated, and gaping greatly at the smaller 

 end; much rounded at the other; covered with a yellowish- 

 brown epidermis ; wrinkled transversely ; inside white. 

 Three inches broad. Inhabits the British coasts. 



Gc?n/s 59.— GALEOMMA.—DaMc/m. 



Generic Character — Equi valve, inequilateral, transverse, 

 with a large oval gape at the front margin ; hinge without 

 teeth, ligament internal. 



Galeomma Turtoni. — Turton's Galeojiima. Plate XV. 

 fig. 8. Tumid in the middle, and gradually sloping to the 

 sides; dull milk-white, coveried with short interrupted opaque 

 lines; beaks prominent and central. Breadth nearly an inch. 

 Inhabits the English channel. 



Genus GO M AGDAL A. —ZeacA. 



Generic Character Transversely oblong-ovate, gaping 



at one end; beaks obtuse; hinge without teeth, but pro- 

 vided with a transverse unconnected plate, attacled to each 

 valve by a cartilage and an oblique descending groove; car- 

 tilage internal. 



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