CONCHYLIA— D/T/fYi?^. 1. 



dinal rib, and on the margin above the teeth is a large rough 

 wrinkled tubercle. 



In its outline this species has a great resemblance to the Pholas 

 parva, but differs in the following particulars. 



The shell is thicker and stronger ; the valves are divided in the 

 middle by a longitudinal groove, and have a corresponding rib on 

 the inside; the transverse ribs are more numerous, and rougher ; 

 the gape is more obicular, not produced into a beak, and in conse- 

 quence the extremities of the valves meet close together behind ; the 

 tubercles on the inside are rough with wrinkles ; and the accessorial 

 valve at the back is truncate and not pointed at the end, and reaches 

 to the anterior extremity of the shell. 



Crispata Pholas testd ovato-oblongd, extremitatihas hiantissimis, margine supra 

 denies mutico. 



Shell oval oblong, very open at both ends, the margin above the 



teeth smoth and without laminar process. 

 Pholas crispata. Linn. Syst. Nat. p. 111. 



Gmelin, Syst. p. 3216. 



Turton, Linn. Syst. iv. p. l73. 



Pennant, Brit. Zool. iv. p. 157, tab 43. fig. 2. 



Chemnitz, viii. p. 369, tab. 102, fig. 872 to 874. 



Montagu, Test. Brit. p. 23. 



Donovan, Brit. Shells ii. tab. 62. 



Turton, Brit. Fauna, p. 145. 



Linn. Trans, viii. p. 32. 



Dorset Catal. p. 27, tab. 3, fig. 4. 



