ORTMANX: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 433 



2. Cambaru.s ijropiriquas, Cauibarus proptiKjuus suiihorni and Camhanis ohscurns. 

 a. Summarn of Facts. (See pp. 362-363; 368-369; 372-373.) 



If we desire to arrive at a proper understanding of the distribution of C. propin- 

 quus, (J. prophupiiia mnhnrhi, and C oh.'icuruii, they must be discussed together. 



The area occupied Ijy these three forms (see PI. XLII, Fig. 3) includes eastern 

 Iowa, southern Wisconsin, nortliern lUinois, Indiana. .Miohigan, ( )hio. northeastern 

 Kentucky, nortliern West N'irginia, western Pennsylvania, western New York, and 

 parts of Canada (Ontario and (Quebec). In the western and northern part of this 

 range C. ■pro]>iii(juus is found ; (J. prophxpiUii sanhoriii occupies the larger part of 

 Ohio and ])arts of Kentucky and West Virginia; while C. ohscurns has its chief 

 domain in western I'emisylvania, passing southward into Must \'irginia and iKjrth- 

 wartl into New York. Thus it is apparent that the three forms occupy different 

 sections of the general area of the group, propbupius being western (and nortliern), 

 sanbonii central, and (iliscurua eastei'n. As far as observations go all three formsare 

 rather jsharply .separated geographically, although they come into contact at the 

 edges of their ranges. This is especially true, as we have seen, in our state and the 

 adjacent portions of Ohio and West Virginia, while in western Ohio and in Indiana 

 nothing is known of the boundaries of the forms represented there. 



In Pennsylvania only two of these forms are found (PI. XLII, Fig. 2). ('. propin- 

 quus is restricted to Lake Erie and its drainage ; C ohscta-us belongs to the Ohio sys- 

 tem, and is found everywhere in the western section of the state, in the Ohio, Mo- 

 nongahela, and .Mleghany Rivers and their tiilnitaries. The l)()undary toward the 

 east is formed liy the divide between the Alleghany and Susquehanna sy.steras, and 

 farther south generally b}' the ("hestnut Ridge (with exceptions to be discussed 

 below). Northward this species eros.ses over into the ( ienes.see drainage, and extends 

 into New York. It also crosses over into the Lake Erie drainage in Pennsylvania. 



Along the western border of the state it pas.ses beyond the state line into Ohio, 

 the drainage belonging in the northern i)art to the Beaver River. Furthermore it 

 goes down the Ohio and is found in all creeks running from Pennsylvania through 

 the Panhandle of West Virginia as far .-^outh as I'ish ( 'ri'ek in ( ireeiir < 'ounty, 

 Pennsylvania, and Marshall ( '<ninty. West N'irginia. Fish ( 'reek falls into the ( )hio 

 a little below iSIouniisvillc West N'iruiiiia. an<l e()ntains only the typical form of 

 C. obscttrus. 



Going further down the Ohio conditions suddenly change. In Fishing ( 'rock, 

 Wetzel County, West \'irginia, which empties into the Ohio near New Martinsville. 

 about thirteen miles below the mouth of Fish ( 'reek, (.'. priip'niipiiiK.idiihonii appears. 

 Put the form hei'e found is not typical. As we have seen above, it inclines some- 



