BIVALVES.— MYA. 



37 



UYk— Gaper. 



Division I. — Hinge with one or two rounded teeth, not inserted 

 in the opposite valve. 



Glycymeris — Great, 

 ♦Truncata — Abrupt. 

 *Arenaria — Sand. 

 *Declivis — Sloping. 

 *Pubescens — Pubescent. 

 *Praetensus — Spoon-hinge. 

 Anatina — Duck. 

 Globosa — Globular. 

 Nicobarica — Nicobar. 



Rostrata — Beaked. 

 *Distorta — Deformed. 

 *Bidentata — Double -toothed. 

 *Decussata — Decussated. 

 ♦Purpurea— P«r/)/e. 

 *Ferruginosa — Rusty. 

 Nitens— Glossy. 

 *Prismatica — Prismatic. 

 *Substriata — Substriated. 



Division II. — Hinge callous, ivithout teeth. 



Edentula — Toothless. Norwegica — Norwegian. 



Membranacea — Membraneous. Siliqua — Bean-pod. 



Division III. — Hinge with teeth inserted into the opposite valve. 



*Batava — Dutch. 

 *Pictorum — Painters'. 

 *Ovata — Oval. 

 Radiata — Radiated. 

 Ponderosa — Ponderous. 

 Complanata — Smooth. 

 Nodulosa — Knotted. 

 ♦Margaritifera — Pearl. 



Corrugata — Wrinkled. 

 Rugosa — Rough. 

 Variabilis — Variable. 

 Nodosa — Knobbed. 

 Syrmatophora — Angular. 

 *Suborbicularis — Roundish. 

 *Inaequivalvis — Inequivalve. 

 Labiata — Lipped. 

 Aurita — Eared. 



Division IV. — Hinge toothless, with a conical rounded hollow for 

 the reception of the cartilage. 



Vulsella — Tweezers. 



