ORTMANN: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 425 
B. GeEoGRAPHICAL DIsTRIBUTION. 
(Plates XLII and XLII.) 
1. Cambarus limosus. 
a. Summary of Facts (see above, pp. 356-358). 
This species belongs to the rivers, ponds, and canals of the lowlands of the At- 
lantic Coastal Plain and the Piedmont region ® in the states of New Jersey, Penn- 
sylvania, Maryland, District of Columbia, and Virginia. It has not been reported 
from the State of Delaware, but must certainly occur there also. 
In Pennsylvania it extends up the rivers to a certain distance and in the Sus- 
quehanna River enters the Alleghany Mountain region. In Maryland it goes up 
the Potomac River, reaching the eastern extremity of West Virginia, thus also en- 
tering the Alleghany Mountain region. 
Thus it is found in Pennsylvania in the drainages of the Delaware, Susque- 
hanna and Potomac Rivers; but it decidedly prefers the region of the lower Dela- 
ware, from the bend of the river at Trenton downward. Here it is exceedingly 
abundant, as also in the lower and quieter parts of the Schuylkill River at Philadel- 
phia. It goes up the Delaware and Schuylkill, and is found in their tributaries 
within the Piedmont region, but here it is by no means as abundant as in the Dela- 
ware. It seems to be absent in the great Alleghany Valley between the Susque- 
hanna and the Delaware, but reaches the foot of the Blue Mountain between the 
Susquehanna and Potomac, occupying the Cumberland Valley (part of the great 
Alleghany Valley), and in the Susquehanna and Juniata it ascends even further, 
far into the Alleghany Mountains (Center and Bedford Counties). 
b. Origin of the distribution of C. limosus. 
In Pennsylvania. 
In the Delaware River above Trenton this species goes up as far as New Hope 
in Bucks County; but is very rare there, (only one specimen was secured by the 
writer after a prolonged search), and it seems that it does not go far beyond this 
point, if at all. Professor A. HE. Davison informs me that it is not found near 
Easton, Northampton County, about ten to fifteen miles from the Blue Mountain, 
and I was unable to find it in the Little Lehigh Creek near Emaus, Lehigh County. 
“As to the division of Pennsylvania into Coastal Plain, Piedmont Plateau, Great Alleghany Valley, Alleghany Moun- 
tains and Alleghany Plateau, see Davis, 1889, p. 187, and Hollister, 1904, p. 10, map, Fig. 1; also Powell, 1896, p. 
73 el seq. and map, and Willis, 1896, p. 169. 
