ON THE PINNA INGENS. 103 



I shall therefore proceed to point out from the 

 works of a few conchological writers, since the 

 time of Pennant, the errors and doubts into which 

 he has led them. The fact is, every writer has 

 followed his own ideas on this subject, no definite 

 distinctive characters having at first been esta- 

 blished. 



Mr Pennant, in vol. iv. page 115. of his 

 " British Zoology," states as follows : " Pinna 

 " ingens, — I saw specimens of some vast pinna, 

 " found among the farther Hebrides, in the col- 

 " lection of Dr Walker of Moffat : they were 

 " very rugged on the outside, but I cannot recol- 

 " lect whether they were of the kind found in the 

 " Mediterranean or West Indies." 



Mr Donovan, in his " Natural History of British 

 " Shells," plate 152., figures and describes a pinna 

 dredged on the coast of Shetland, now in the cabinet 

 of A. Macleay, Esq; and names it Pinna l&vis. He 

 is induced to give it this name, he says, " from the 

 " difference to any other shell of this genus before 

 " described, as British," (and adds,) " if we are 

 " not mistaken, from either the Linnean or 

 " Gmelinian species of the genus also ;" though it 

 appears clear, that if Pennant's definition of Pinna 

 ingens had been referred to, a strong characteristic 

 would have been found, viz. the ruggedness of 

 the outside. This would have agreed well with Mr 

 Donovan's description, " Valves rugose on the 

 u posterior parts." 



G 4 



