113 



G R Y P H tE A Coliimba. 

 TAB. CCCLXXXni.~Fig. 1 and 2. 



Spec. Char. Ovate rounded, expanded pos- 

 teriorly, smooth ; beak attenuated, incurved, 

 oblique. 



Syn. Gryphaea columba. Lam. Hist. Nat. VI. 

 pt. 1. 198. Knorr petr. Vol. III. tab. D. 

 Ill, c. 



XTERHAPs this is the smoothest species of Gryphaea 

 known ; except towards the margin, there is hardly a 

 single sharp projecting line of growth to be found ; the 

 anterior lobe is small, but well defined ; the left or 

 upper valve is more or less square in form, and largely 

 waved, its posterior edge is very thick, flattened, and 

 striated near the hinge, every where else the edge is thin 

 and sharp ; the depth of the attached valve is about half 

 its width; it is obtusely keelformed ; the surface of 

 attachment is very ndririute, at the point of the involute 

 beak. 



If we may judge by the characters of the stone this 

 shell is preserved in, it belongs to some part of the Green- 

 sand formation contiguous to the Chalk ; the only 

 British specimen that I have ever seen, was given me 

 many years ago by my lamented Friend Mr. Cuunington, 

 who obtained it from Northamptonshire ; it is represented 

 in the lower figure. The upper figure is taken from a 

 French specimen from Mans ; it is in a much better state 

 of preservation than the English one. 



Fig. 2. is the variety h of Lamarck, with a striated 

 beak, it is also from Mans ; I have added it to shew the 

 hinge which approaches that of Chama in appearance, 

 since it has the rudiments of a tooth, and the hinge pit 

 very much curved. 



