Historical Account of Testqceological Writers. 205 



to divide; and he forms three from the authority of Linnaeus him- 

 self, if Acharius (by whom the information of Linnaeus's intentions 

 was communicated to Retzius) be correct. There can be no 

 doubt that the My a Perna of the Si/st. Nat. admits of being made 

 a distinct genus, under Avhich ma\% very properly, be compre- 

 hended some of the ventricose species of Mytilus. The appella- 

 tion of Perna is accordingly given to this family, and that of 

 Unio to the' two perlaceous species of Mya, viz. Margarififera and 

 Pictoriim. 'I'he four last species of the original genus Ostrea ap- 

 pear to have been afterwards intended by Linnaeus to form an- 

 other family, to be called Melina. According to our author, the 

 Anomia consists of four very different divisions of shells, which he 

 proposes to designate by the generic terms of Anomia, Crania, Te- 

 rebratida, and Placenta. By turning to the Anomice as they stand 

 in the 12th edition of the Syatema, the reader Avill easily discover 

 what species are meant to be comprehended under each of these 

 genera; and how partial soever he may be to the original arrange- 

 ment of Linnaeus, he will not be disposed, perhaps, to accuse the 

 Testaceologist of whom we are treating of any rashness of reform. 



There is a scientific description, Avith figures, of Venus liihophaga, 

 published by the Professor in the Mem. de VAcad. Roy. des Sc. for 

 1786. 



In the same Avork for 1788 we find an author of the name of 



LE GEXTIL, 



who describes a Patella (apparently the ccerulcata) found on an 

 aquatic plant, which, with the shell, is figured in the 20th plate 

 of that volume. 



CORDINER. 



In the plates accompanying Mr. Cordiner's Description of 

 Ruins, &c. in North Britain arc several figures of Testacea, Avliich 



are 



