OP CONCHOLOGY. 53 



may be found on the reflux of the 

 tide. 



In Turton's Linne nineteen of this 

 genus are described ; and six species 

 have been found in the British seas. 



The French conchologists have di- 

 vided this genus into two : Donax and 

 Petricola. 



Genus 10th - VENUS. Animal a 

 Tethys ; shell bivalve, the frontal mar- 

 gin flattened, with incumbent lips; 

 hinge with three teeth, all of them 

 approximate, the lateral ones diver- 

 gent at the tip. Linn. Syst. 309. 

 Plate 6th, fig. 10th. 



This genus is divided into two sec- 

 tions : pubentes* and impuberes .** 

 This latter section is divided into three 

 families : subcordata?^' orbiculatae,*! -f- 

 and ovalis.ff ~\- 



Dr. Turton has not followed Linne 

 in the above arrangement, but has 

 divided them into three sections; A 

 somewhat heart-shaped, B orbicular, 



