OKTMANN: THE CKAWFISHES OF THE STATE OF PENNSYLVANIA 367 



2. The hand of the achilt male of the first form lias a distinct tendency to 

 become broader than in tlie typical projnnquu.s. This 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 lari^er 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. The.se 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 < '. 

 obscarus, where similar tubercles are present in larger individuals. 



3. The two spines of the lower side of the carpopodite are almost alwa^'s well 

 developed. There are a 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 pos.sessing old worn sliells, 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 chelae, 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, AA'. \'a., has on the left 

 carpopodite a small, l)ut sharp, accessory spine behind the large median spine. 



4. Tlie 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 indistinct, due to wear) ; the outer lower margin has an 

 anterior spine, and often a tuljercle 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 ^lid- 

 dle Island Creek this second spine is very prominent on the left meropodite. 



5. The male copulator}' organs are of the j^ropinrfius-iype, 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 tii-st 

 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 



