EXPLANATION OF PLATES. 



[The drawings are made from specimens for the most part con- 

 tributed by Professor Buckman and Darell Stephens, Esq. They 

 are drawn on stone, and are kindly contributed by T. Davidson, Esq., 

 F.R.S., who is not only a good naturalist, but an accomplished artist. 



Each species has been drawn of the size of nature, and in such 

 different positions that it would be next to impossible to mistake 

 the species intended. EDITOE.] 



PLATE I. 



Fig. 

 1, 2. Terebratula perovalis, (var. Ampla Buck.} ; Bradford 



Abbas (p. 74). 

 3. Terebratula Stephani (Dciv.} ; Broadwinsor, collection of 



Mr. D. Stephens (p. 74). 



