392 MACTRA. FLAT-SIDED COCKLE. Cl. VI. 



GENUS IX. MACTRA. FLAT-SIDED 

 COCKLE. 



Animal, a Tethys. 



Shell unequal-sided, equivalve. 



Tooth, middle, complicated ; with a little con- 

 cavit}'' on each side ; the lateral teeth re- 

 mote, mutually received into each other. 



1. DEAL- M. pellucida. Gm. Lin. Lin. Tr. viii. 68. t. \,f. 10. 



3260.? Mont, Test. Br. Q5. t. 5. 



BATA. 



* 



M. with an ovate gaping shell, the middle 

 hinge tooth complicated, with a lateral small 

 tooth ; length an inch and a quarter, breadth an 

 inch and three quarters. 



Found at Weymouth. 



2. GLAUCA. Gm. Z.W. 32(>0. Mont. Test. Br. b'l. 



Lin. Tr. viii. 68. 



* M. with an ovate dull white shell, radiated 

 with grey, most delicately striated transversely ; 

 the anterior end wrinkled ; length three inches 

 and an half, breadth four and an half. 



