368 MEMOIRS OF THE CARNEGIE MUSEUM 
the first form collected in Fishing Creek, West Virginia, only two had no trace of 
it; six had a curve developed in its place, and in five others it was distinct, in one 
or two representing a blunt angle. The length of the tips of this organ varies 
slightly, but it is generally less than in C. obscwrus. The tip of the inner part 
always corresponds to that of the Oberlin specimens, being compressed and rounded 
off. 
6. The annulus of the female is always of the propinquus-type, that is to say, 
flat, with no tubercles. In old females it becomes a little uneven, the anterior and 
posterior parts being slightly swollen, but there are never two distinct tubercles as 
is the case in C. obscwrus. 
We may condense the varietal characters of this form as follows : 
C. propinquus sanborni clearly is nearer to propinquus than to C. obscurus on 
account of the lack of a distinct shoulder on the anterior margin of the copulatory 
organs of the male of the first form, on account of the general shape and size of this 
organ, and further, on account of the flat female annulus. It differs from C. pro- 
pinquus in the flattened and rounded tip of the inner part of the male organ, in the 
lack of a median keel on the rostrum, and in the shape and armature of the cheli- 
peds, although the latter differences are slight and not always reliable. Just in the 
latter characters, and in the tendency to develop a notch on the anterior margin of 
the male organ, it inclines toward C. obscwrus. Thus it is clearly a transitional 
form toward C. obscurus of western Pennsylvania, and its geographical distribution, 
as we shall see below, is also intermediate between C. propinquus and C. obscurus. 
The colors of C. sanborni agree throughout with those of C. propinquus and 
C. obscurus. ‘The color of the newly laid eggs is dark olive-green, sometimes almost 
black. 
There are one hundred and sixteen specimens of this variety at hand; five are 
from the Lake Erie drainage in northern Ohio; eighty-one from the Tuscarawas 
drainage in eastern Ohio, and thirty from Fishing and Middle Island Creeks in West 
Virginia. 
DISTRIBUTION. 
(See Plate XLII, Fig. 3.) 
LOCALITIES REPRESENTED IN THE CARNEGIE MUSEUM. 
Onto: Lorain County, Waterworks Reservoir, Oberlin (R. L. Baird coll., exch. 
Mus. Oberlin); Stark County, West Branch of Nimishillen Creek, Canton; Carroll 
County, Conotton Creek, New Hagerstown; Harrison County, Conotton Creek, 
Bowerstown; Tuscarawas County, Dennison (V. Sterki coll.). 
