DIMYARIA. 161 



Anatina decUvis. — 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 LinncBus. 



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 Mya. 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. 



Genus 59— GALEOMMA.— Dawc^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 Galeomma. Plate XV. 

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

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

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

 Inhabits the English channel. 



Genus 60 M AGDAL A. —Zeac^. 



Generic Character Transversely oblong-ovate, gaping 



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

 vided with a transverse unconnected plate, attached to each 

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

 tilage internal. 



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