174 JMiscellanies. 
are compressed in most specimens; and the next change we find, is 
in the Hyria avicularis, (Lam.) in which the cardinal tooth is some- 
what lamellar and forms nearly a line with the lateral tooth. The 
next ‘nuance’ is in the Symphynota levissima, (Nob.) which pos- 
sesses lamelliform cardinal and lateral teeth forming nearly a com- 
plete arc. Then follows the Symphynota bi-alata, (Nob.) the uninter- 
rupted curved tooth of which is little more than an elevated line under 
the ligament and beaks. As far as one may be able to judge from a 
bad description and very bad drawing, the Dipsas plicatus, (Leach,) 
may be with propriety placed at the end of this suite.” 
Mr. Lea’s critical examination of Lamarck’s species of the genus 
Unio constitutes a valuable part of the introduction to his paper, read 
before the Philosophical Society, March 6th, 1829; and we extract 
the substance of it for the satisfaction of those persons who may 
ever have exercised themselves with the determination of Uniones by 
the aid of Lamarck. 
Alasmodonta margaritifera. Say. 
Mya margaritifera. Lin. 
There can scarcely be a doubt but 
that it is a young shell of No. 1. 
Consists of the ponderous varieties 
of several species. . 
Embraces the plicata of Le Sueur, 
the crassus and undulatus, of Barnes, 
the rariplicata and crassidens of 
Lam. and the undulata and dombey- 
ana of Valenciennes. Le Sueur’s 
name must take the precedence. 
Its habitat is probably the U. one 
and not Peru. 
1. U. sinuata, Lam. 
3. U. crassidens, Lam. 
2. U. elongata, Lam. i 
4. U. peruviana, Lam. 
5. U. aoa Lam. A variety of No. 4. 
' pea in every respect to the 
6. U. purpurata, Lam. yeae but in habitat. 
: . Descriptions too imperfect to ad-— 
E is im —_ J ii of their being identified with 
0 i relent See any of our individuals; although 
piliekaa sara yee are all from this country. 
10. U. rarisulcata, Lam. 
11. U. coarctata, Lam. Mere varieties of the complanatus. 
12. U. purpurascens, Lam. 
