* 
1883] Note on the Genus Campeloma of Rafinesque. 607 
haps further eastward, a sixth distinct form predominates, seem- 
ing to replace all the others, the Campeloma subsolidum Anthony. 
The form decisum also occurs in the northern portions of the 
same State. From the Mississippi river, at a single station in 
Mercer county, are collected peculiarly constructed forms which 
may, until more is known about them, be doubtfully assigned to 
Anthony’s swbsolidum. They have been described by Dr. Isaac Lea 
as Campeloma milesii, his type, however, coming from Brand lake, 
Michigan. Specimens of the same form have been received from 
Arkansas. The forms thus far mentioned would appear to com- 
prise all the species found in the Northern United States. Pass- 
ing to the south of the great drainage system of the Ohio river, 
including the Tennessee and Cumberland drainage areas, only two 
forms appear common in some portions of the area we have de- 
scribed, the Campeloma ponderosum Say, and C. rufum Halde- 
man. The first of these attains a great size and high degree of 
perfection in the Warrior, Alabama and Coosa river systems, as 
well indeed as in the Tennessee river, in that portion of its course 
which lies in the State of Alabama. The second species, Cam- 
peloma rufum Hald., is taken in some numbers in the Hiawassee 
river in Tennessee, where its forms exhibit great beauty and per- 
fection, It should be remarked, however, of the shells from Ala- 
bama which have been referred to this species, that grave doubts 
are entertained of their correct determination ; the facts connected 
with them pointing to a distinct and probably new species. In 
all the shells which are thus known to be common to the two 
areas, are presented some very interesting facts bearing on the 
influence of environment on animal life. Over this last area, and 
beyond toward Louisiana, occur other forms which, in a critically 
accurate revision of the genus, it will be necessary to recognize 
as good and distinct species. They are Campeloma decampu W. 
G. Binney, occurring in the Tennessee drainage of North Alabama 
and south to the confluence of the Coosa and Tallapoosa rivers, 
n the Coosa and Cahawa rivers occurs a form described as Cam- 
beloma nolani Tryon, which it will also be necessary to recognize. 
n a few of the collections in which it has been placed it bears the 
name of ponderosum, but would seem to be sufficiently distinct. 
F rom this same State there has been described, by Dr. Lea, a 
form known as Campeloma coarctatum, said also to occur in South 
Carolina, Mississippi and Arkansas. 
