190 Mis Sheppard ov 
Animal with a compressed thick foot at one extremity, at the 
other sending forth a large tube.” 
These shells are readily distiiguished from Unio, which 
Linnceus had placed in tne sane genus, by their bread per- 
pendieular tooth. 
Mya aremaria. “Shell ovate, anterior side rownded, eardinat 
tooth denticulated 2” inbabits near the mouth of this river— 
the large tooth is very sharp at the summit, the shell is of a 
whitish colour tinged with yellow of reds 
Coxcne, ninth family. 
Venus. “Shelf equivalve, tnequilatera}, transverse or orbt- 
cular, three cardinal teeth, on each valve, aproximate at their 
base, lateral oncs spreading obliquely open towards the 
summit, ligament external.” 
«The animal is possessed of two-tubes which it often sends 
out beyond the shell.” 
Venus mercenaria. ‘+ Shelf sofid obliqaely cordate, trans- 
versely striate, and sulcate ; within white, witha large vio- 
let spot en the anterior side.” ‘Fhis species is sometimes 
brought wp with oysters. from the gulf ; it is a course heavy 
shell of a grayish colour, not in the least pretty, although be- 
Jonging to the most beautiful family of the Conchifera, 
Narov< thirteenth family. 
As the Naiada are all river shells, it is probable there may 
be several of them: indegenous. 
Unio. ‘Shell transverse, equivalve, incquilateral: ; beaks 
deeorticated, hinge with two teeth on each valve, one eardinal 
short, mostly lobed, or bifid, substriated ; the other elonga- 
ted compressed ; lateral extending under the corselet, along 
the lower margin :’? this genus fermed by Bruguier out of 
some of the Linnwan Myas, is by DeLanarck removed seve- 
ral families from them. 
These stiells as DeLanarck observes, ren one into the other 
to such a degree, that the species are rendered very wucertain. 
We 
