NEW FRESH WATER AND LAND SHELLS. 7 
Remarks.—A single specimen only of this species was received from Dr. Troost. Like 
the P. corpulentus, (Say,) it is covered*with strie, but in the del/us they are much closer and 
more regular. It is a much less inflated shell, and more regular in its form. 
PHYSA. (Lamarck.) 
The genus Physa, established, as some authors say, for the reversed species of Lymnea, 
is abundant in the fresh waters of our country. There have been twelve species hereto- 
fore described as inhabiting the United States, and I now propose to add three more to 
the number. 
As to the propriety of the separation from Lymnaea, I have no doubt. To those who 
have been familiar with many species of the two genera, their distinctive characters will, 
I think, be perfectly apparent. Lamarck described only four species. 
Paysa HiItpReTHtiana. 
Test ellipticd, subcompressd, longa, subpellucidd; spird obtuso-elevatd; anfractibus quinis; labro marginato; 
apertura longd, compressa, 
Shell elliptical, somewhat compressed, long, somewhat pellucid; spire obtusely elevated; whorls five; lip margined; aper- 
ture long, compressed. 
Hab. A lake in Illinois, Dr, Hildreth, My Cabinet, and Cabinet of Dr. Hildreth. Diam 40, 
Length .75 of an inch, 
Remarks.—This species is among the largest, and is perhaps the most remarkable Physa 
yet observed in this country. The aperture is little more than half the length of the shell. 
The apex is very obtuse, and the whole shell is somewhat cylindrical. A single speci- 
men was brought by Mr. Nicklin from Dr. Hildreth, and I name it after him, as he seems 
first to have observed it. 
PHYSA INFLATA. 
Testa inflatd, tenebrosd, subpellucidd; spird subelevatd, acuto-conicd; anfractibus quinis; labro marginato inflato; 
apertura lata. 
Shell inflated, dark, somewhat pellucid; spire somewhat elevated, acutely conical; whorls five; outer lip margined and 
inflated; aperture wide. 
Hab. Virginia, between the Salt Sulphur, and the Sweet Springs. P. H. Nicklin, My Cabinet and 
Cabinet of Mr. Nicklin, Diam. 48, Length .65 of an inch. 
Remarks.—T wo specimens were taken by Mr. Nicklin in a small stream which crosses 
the road in a gap in the main chain of the Alleghany Mountain between the Salt Sulphur 
and the Sweet Springsin Virginia. The gap is nearly level for several miles, and some of 
the streams run to the West and some to the East. This Species seems to me to differ 
from any with which Tam acquainted. It is perhaps most nearly allied to P. heterostropha, 
(Say,) but has a shorter aperture and is more inflated. 
Puysa TRoostiana. 
Testa ellipticd, subcrassd, luteo-fuscd, levi; spird obtusd; suturis subimpressis; anfractibus quinis, subconveis: 
labro marginato, intus incrassato; apertura parvd, ovatd, contractd. 
Shell elliptical, rather thick, yellow-brown, smooth; Spire obtuse ; sutures slightly impressed; whorls five, 
‘ slightly con. 
vex; lip margined, thickened within; aperture small, ovate, contracted, 
