466 MEMOIRS OF THE CARNEGIE MUSEUM 
(a) Conemaugh drainage, with only one species: C. bartont. 
(b) Ligonier Valley, with two species: C. bartoni and obscurus. 
(c) Headwaters of Indian Creek, with three species: C. obscwrus, bartoni, and 
carolinus. ‘This latter section also comprises the northeastern corner of Fayette 
County. 
The greatest number of species found in any one county is five, namely, C. 
obscurus, bartoni, carolinus, monongalensis, and diogenes. This is the case in West- 
moreland and Fayette Counties. They may be found in close vicinity only along 
the escarpment of the Chestnut Ridge. For the rest fowr is the largest number of 
species found closely associated, namely the four belonging to the second area, com- 
prising the range of C. monongalensis. 
In conclusion, attention should be called to the fact that the terminal moraine 
in no case constitutes a barrier for any of the Pennsylvanian crawfishes. (Compare 
Lewis’ map, 1884, with our maps, Pl. XLII and XLIII.) Of course, for the river- 
species the moraine would not be of any consequence, and of the burrowing species, 
two, C. carolinus and C. monongalensis, do not reach it at all, while C. diogenes has 
crossed it in the west. But instead of being a barrier the glaciated area rather 
seems to offer more congenial conditions on account of the frequency of swampy 
places (kettleholes). ; 
The question remains, whether our survey of the state is to be regarded as com- 
plete and exhaustive, or whether there might be other species within its limits. This 
is suggested by Faxon (1885a, p. 165) as to Cambarus blandingi (Harlan). This 
species is found in New Jersey at Trenton, on the Delaware meadows just opposite 
the eastern extremity of Bucks County, Pennsylvania, associated with C. limosus 
(Faxon, l.¢., p. 22 and 88). I have made a careful search for it in this part of the 
siate, and visited this corner twice (Sept. 15, 1904, and at the same date, 1905). 
Having collected this species previously in New Jersey, I was acquainted with its 
ecological habits and knew where to look for it. I indeed found localities that 
appeared favorable, but I failed to see any traces of the species. I think it is quite 
safe to assert that this species is not found in this state. 
- The case of Lake Erie is a little different. We have records showing that in 
Ohio the western extremity of the lake is inhabited by Cambarus rusticus Girard and 
C. immunis Hagen. The former has been reported from Kelley’s Island (Faxon) 
and from Sandusky Bay (Osburn and Williamson), and from several tributaries of 
the lake. The latter is mentioned from Lake Erie, off Lorain County (Osburn and 
Williamson), and from tributaries of the lake as far east as Lorain County. C. 
rusticus is not found anywhere further east, and it seems doubtful whether it finds 
