PLATE X, 



Dr. Rutty mentions a Pinna ten inches long and five broad, caught 

 near the Skerries, in Ireland ; and Mr. Pennant " saw specimens of 

 vast Pinna, found among the farther Hebrides, in the collection of 

 Dr. Walker, at Moffat" but it is uncertain of what species either 

 of these were : Mr. Pennant says, " they were very rugged on the 

 outside, but cannot recollect whether they were of the kind found in 

 the Mediterranean or West Indies *.' y 



The only British species of Pinna we are acquainted with, is the 

 P. Muricata of Linnaeus, or P. Fragilis of Pennant, and that is very- 

 rare. The latter author describes it from a specimen in the Portland 

 cabinet, which had been fished up at Weymouth, in Dorsetshire. Da 

 Costa says, he has seen a very small one (of the same species) from the 

 coast of Wales. — Both of these are represented in the annexed plate. 



This Shell is extremely thin and brittle, and gapes open at the 

 broadest end. It is semi-pellucid, and of a horn colour ; the outside 

 marked with longitudinal ribs, roughened with rows of small prickles f. 

 The inside is smooth, of a pale horn colour alfo, with a pearly lustre 

 towards the top. 



* This Author, however, arranges It as a new British species, without further de- 

 scription : — as, Pinna Ingens — Great Nacre. 



•j- In Pennant's figure these are obsolete* 



