56 



CONCHIFEKA. 



Gorbula (Bruguiere). Shell roundish, nearly 

 equal-sided, very unequal- valved ; hinge a tooth in 

 one or both valves, with socket and ligamental pit 

 beside it. Animal with very short united siphons ; 

 fringed orifices ; mantle opening for the passage of 

 a narrow thick foot ; anal siphon with a projecting 

 tubular membrane. 



C. nucleus. Fig. 73 ; n. s. 

 rosea. 



Sph&nia (Turton). Nearly as Corbula. Shell 

 oblong ; hinge an erect dilated tooth in one valve, 

 and a socket in the other. 



S. Binghami. Fig. 74 ; n. s. 



My a (Linn.). Gaper. Shell rhomboidal, equal - 

 valved ; hinge a spoon-shaped process in the left 

 valve, and a socket in the right. Animal with 

 united retractile siphons, and a small conical foot. 



M. truncata. Fig. 75 ; \ n. s. 

 arenaria. 



FAMILY V. SOLENID.E. 



Shell greatly dilated, parallel-sided, gaping at 

 both ends ; ligament external ; hinge with com- 



