Historical Account of Testaceological 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 MyaPerna of the Syst. Nat. admits of being made 
a distinct genus, under which may, 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 
U/iio to the two pcrlaceous species of Mya, viz. Murgaritiftra and 
Pictorum. The four last species of the original genus Osirea ap- 
pear to have been afterwards intended by Linnaeus to form an- 
other family, to be called Melina. According to our author, tin.' 
Anomia consists of four very different divisions of shells, which he 
proposes to designate by the generic terms of Anomia, Crania, Te- 
vcbratula, and Placenta. By turning to the Anomice as they stand 
in the 12th edition of the Sy sterna, the reader will 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 acouse the 
Testaceologist of whom we are treating of any rashness of reform. 
There is a scientific description, with figures, oiVenus lithophaga, 
published by the Professor in the Mem. de VAcad. Roy. des Sc. for 
1786. 
In the same work for 1?88 we find an author of the name of 
LE GENTIL, 
who describes a Patella (apparently the caruteata) found on an 
aquatic plant, which, with the shell, is figured in the 20th plate 
of that volume. 
CORD1NER. 
In the plates accompanying Mr. Cordiner's Description of 
Ruins, &c. in North Britain are several figures of Testacea, which 
are 
