6 



PLICATULA inflata. 



TAB. CCCCIX-^j%. 1 



Spec. Char. Suborbicular, gibbose, rathet 

 smooth, furnished with a few ridges and de- 

 pressed spines; both valves convex. 



Syn. Plicatula spinosa, Mmitell GeoL Sussex, 

 p, 129, /. 26,/. 13, iQ and 17. 



X HIS is probably the largest species of Plicatula known : 

 the smooth surface, and the small number of the ridges, 

 composed chiefly of depressed spines, suffice to dis- 

 tinguish it from the last, and the convexity of both valves 

 will distinguish it from most Oysters. 



Small specimens of this have been taken for Plicatula 

 spinosa by Mr. Mantell, but it is a very distinct 

 shell ; it is found only in the lower beds of Chalk with- 

 out flint,, and that called sometimes Chalk Marl, but 

 not in the Clay beneath. 



The specimens figured, were kindly lent me by Pro- 

 fessor Sedgwick; they are from the vicinity of Cam- 

 bridge : I have others from Hanisey, by favour of Mr. 

 Mantell. 



