CONCHIFERA. 



267 



equilateral; bosses small, and pointed, the outer surface 

 sculptured ; cardinal and lateral teeth distinct, but variable 

 in number. Animal orbicular, its mantle freely open in 

 front, with plain or fimbriated edges ; siphonal orifices 

 sessile ; the anal sometimes provided with a retractile pro- 

 duced tube (anal valve ?) ; foot very long, ligulate, tubu- 

 lar ; branchial leaflets of each side united into one ; labial 

 palpi obsolete.* — 69 species f; also fossil. 



A pretty genus of bivalves : they are found in Europe, 

 America, New Holland, &c, and six are British. 



Fimbria. Muhlf. (Corbis Cuvier ; Idothea Schnm.) — 

 Shell transverse, equivalve, nearly 

 equilateral ; bosses curved inward- 

 ly ; cardinal teeth two, lateral two, 

 one of which is remote. Animal 

 not much known ; according to Va- 

 lenciennes it has only one gill on 

 each side, and no lip appendages. 



— 2 species ; also fossil. 

 The shells of this genus are thick 



and solid : there are few species in 

 a recent state, and they are rare. They may be easily 

 distinguished by the longitudinal and transverse undu- 

 lations or ridges crossing the external surface of the 

 valves. The species known to Linnseus he named Venus 

 jimbriata, it is of a white colour, and tinged with pink 

 occasionally. They are from India. 



Diplodonta. Bronn. (Mysia Gray, not of Leach.) 



— Shell equivalve, more or less suborbicular, inequilateral, 

 nearly smooth or marked by lines of growth ; hinge com- 



* Forbes's British Moll. 



f Reeve's Ieoniea, 



