460 MEMOIRS OF THE CARNEGIE MUSEUM 



(«) Conemaugh drainage, with only one species : ('. Ixirtoiti. 



{h) Ligonier Valley, with two species: C. bartoui and uhscnrus. 



(c) Headwaters of Indian Creek, with three species: C. obscurus, bartoni, and 

 carolmus. 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, earolinus, monoiigalensis, and diogenes. This is the case in West- 

 moreland and Fayette Counties. They may be found in close vicinity oidy along 

 the escarpment of the Chestnut Ridge. For the rest four is the largest number of 

 species found closely associated, namely the four belonging to the second area, com- 

 prising the range of G. rnonongalensis. 



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, PI. XLII and XLIII.) (3f course, for the river- 

 species the moraine would not be of any consequence, and of the burrowing species, 

 two, C. carolinns and C. monongalensis, do not reach it at all, while C dlogcve.-^ 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 (1885«, p. 165) as to Cambaru>: blandingi (Harlan). This 

 species is found in New Jersey at Trenton, on the Delawai'e meadows just opposite 

 the eastern extremity of Bucks County, Pennsylvania, associated with C. Ihaoms 

 (Faxon, 1. c, p. 22 and 88). I have made a careful search for it in this part of tbe 

 svate, and visited this corner twice (C^ept. 1.^, li)()4, 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 

 ( )hio the western extremity of the lake is inhabited by ('(ludidru^ nisficus Girard and 

 C. immunis Hagen. The former has been reported from Kcilcy's Island (Faxon) 

 and from Sandusky Bay ((Jsburn and Williamson), and from several tributaries of 

 the lake. The latter is mentioned from Lake Erie, off Lorain ( ounty (Osburn and 

 Williamson), and from tributaries of the lake as far east as Lorain County. C. 

 rmticm is not found anywhere further east, and it seems doubtful whether it finds 



