66 



The spines are more truly aculeate, or like the prickle on a 

 rose-stalk, somewhat flattened longitudinally with the shell, 

 seldom contrary, as in the other shells. The larger spines have 

 a canal or narrow furrow ; in the other species they are 

 often dilated, especially at the narrow side. The spines 

 on the narrow side are all curved towards the hinge, and on 

 the broadest side they are curved from the hinge. 



We are confirmed in our opinion of its being a species, 

 by seeing fine specimens in Lady Wilson's cabinet, and a 

 large one which Dr. Grey was so good as to show us at the 

 British Museum. The latter is at present without a name, 

 and is as large as C. acideatum is commonly found*; other- 

 wise the spines near the hinge of C. aculeatum might lead 

 us to think them the same species. 



* Above twice the size of the Figure, with all the spines flat. 



