ORTMANN: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 367 
2. The hand of the adult male of the first form has a distinct tendency to 
become broader than in the typical propinquus. his is well shown in the largest 
male from Oberlin. However, this may be due to the fact that the specimens of 
this variety at hand are larger than those of the typical form. I notice, however, 
in specimens from the Tuscarawas drainage and from West Virginia, a tendency in 
old specimens, chiefly males, to develop on the upper surface of the hand, near the 
double row of tubercles of the inner margin, additional low tubercles. These may 
be scattered over the inner half of the surface, or a few of them (3-5) may form an 
indistinct row between the upper articular tubercle with the carpopodite and the 
articular tubercle with the dactylopodite. This is a distinct approach toward C 
obscurus, Where similar tubercles are present in larger individuals. 
3. The two spines of the lower side of the carpopodite are almost always well 
developed. There area number of specimens where they are only bluntly spiniform, 
or even tubercular, but this is apparently due to wear, a large number of the speci- 
mens at hand having been collected in spring, and possessing old worn shells, which 
had gone through the winter. In a few cases the tubercle on the anterior margin 
is barely indicated, but all these are cases of regenerated chelee, as indicated by 
their size. The armature of the inner margin of the carpopodite entirely corre- 
sponds to the Oberlin specimens, old specimens developing additional tubercles on 
the upper side. A large female from Middle Island Creek, W. Va., has on the left 
carpopodite a small, but sharp, accessory spine behind the large median spine. 
4. The armature of the meropodite is similar to the Oberlin specimens. There 
is always a series of small teeth behind the anterior spine of the inner lower margin 
(in old shells they may be indistinet, due to wear); the outer lower margin has an 
anterior spine, and often a tubercle or a small spine behind it. The latter is very 
frequent in specimens from the Tuscarawas basin, while in those from the tributaries 
of the Ohio in West Virginia it is rare; nevertheless, in the large female from Mid- 
dle Island Creek this second spine is very prominent on the left meropodite. 
5. The male copulatory organs are of the propinquus-type, that is to say, without 
a shoulder. There is, however, a distinct tendency, not noticed in the Oberlin 
specimens, to develop at the anterior margin a small notch in the male of the first 
form, and it seems that this tendency increases in specimens taken toward the 
south. Out of ten males of the first form collected at Canton, Ohio, five have no 
trace of this notch, two have a slight curve in its place, and three show it clearly. 
This notch in these cases never assumes the shape of a “shoulder.” In specimens 
from Conotton Creek in Harrison and Carrol] Counties, Ohio, (only a few males of 
the first form are at hand), no notch was observed. But out of thirteen males of 
