MOLLUSCA. 79 
of Natural History at Paris. But the truth is, that it was 
found by M. Cortezi, Counsellor at Parma, and a success- 
ful investigator of the organic remains of that district. It 
ought, therefore, to have obtained the name of P. Cortezi, 
in honour of the discoverer, instead of the name of Faujas 
St. Fond, who received it from M. Cortezi, and whose sole 
merit in the subject consisted in his bringing it in safety 
to Paris. 
The principal error of Linnzeus in the construction of this 
genus, consisted in the insertion of fluviatile shells among 
his marine species. Bruguiére readily perceived this error, 
and formed a new genus for their reception, which he called 
Unto. But this group, now denominated Nayapers by La- 
mark, includes the genera unio hyria, anadonta tridina, and, 
we may add, alasmodon. 
5. Soten.—This genus has undergone few changes since 
the days of Linneus. The character has been somewhat 
restricted, and those species have been removed, in which 
the external margin is a little arcuated, and the cardinal 
teeth articulated, and two in number, and formed by Lamark 
into a new genus, which he terms SANGuINOLARIA. The 
animals of this genus, according to Poli, differ from the so- 
lens, in having the tubes of the syphon separate, and of 
unequal length and thickness. The S. ménutus of Linneus, 
found in our seas, is referred to the genus HIATELLA by 
Cuvier, a genus very imperfectly defined, but nearly allied 
to, if it be not identical with, the byssomia of the same au- 
thor, which includes the mytilus rugosus of Linnzeus. 
6. TreLiinA.—This extensive genus of Linnzeus, the es- 
sential character of which is to have an anterior inflection 
or fold in each valve, and lateral teeth, includes many shells 
which differ greatly in form and habit, and which disagree 
