ORTMANN: THE CRAWFISHES OF THE‘ STATE OF PENNSYLVANIA 451 
northwest a more continuous and solid colony has remained. he scarcity or even 
absence of the typical bartont in Erie County, Pa., which in our state is the chief 
domain of C. bartoni robustus, would support this view. C. bartont has not yet in- 
vaded this region to such a degree as to crowd out the other form. Though I must 
confess that it does not strike me as very likely that the smaller form should be able 
to conquer the larger one. 
Further investigations on this question should be made outside of this state. 
5. Cambarus carolinus. 
a. Summary of Facts. (See pp. 396-397.) 
This species (see Pl. XLIII) is found in Pennsylvania in the southern part of 
the Alleghany Plateau, between the Chestnut Ridge in the west, and the Alleghany 
Front in the east, preferring the high valleys in this region, but not going up to the 
highest elevations of the mountains. Thus, although abundant near Meyersdale in 
Somerset County, it does not go up the valley of Flaugherty Creek toward Sand- 
patch. I have searched for it in vain between Meyersdale and Keystone, and at 
Sandpatch. In a northern direction this species ranges in the valley between the 
Chestnut Ridge and the Laurel Hill Ridge as far as southern Westmoreland County. 
Here the northern boundary is formed by the cross-divide in this valley separating 
the headwaters of Indian Creek from the Ligonier Valley. I am quite positive of 
this boundary, since I have searched in vain for chimney-builders all over Ligonier 
Valley from Idlepark (below Ligonier) to the sources of the Loyalhanna River. 
Coming across the divide to Jones’ Mills, within a short time I discovered this species. 
In the longitudinal valley between the Laurel Hill Ridge and the Alleghany Front, 
this species has advanced further north. It has crossed the divide between the Cas- 
tleman River drainage and that of Stony Creek (tributary to the Conemaugh), and 
I found it near Listie and Windber, in Somerset County. At the latter place it seems 
to attain its northern boundary. At allevents I failed to find it near Lovett in Cam- 
bria County, in the high valley of Laurel Run, which to all appearance affords con- 
genial conditions for its presence being rather swampy in many places. I have also 
searched for it unsuccessfully in the region of Cresson, Cambria County, and at 
several places further north. 
The rest of the range of this species is entirely to the south of this state, in 
Maryland, West Virginia, Virginia, North and South Carolina (disregarding the 
isolated report from the Indian Territory, in which I do not put much faith). No 
particulars are known about its boundaries, but in this region also it is restricted to 
the mountains. 
