iyo S .] ORTM ANN — AFFINITIES < >F CAMBARUS. 123 



east, parallel to the strike of the mountains. This species, how- 

 ever, has also been reported from Indian Territory (Ozark region). 

 This locality is very strange, and at present is not connected with 

 the main range, no localities being known in Missouri, Arkansas 

 or the larger part of Tennessee (except the eastern extremity). 

 But it is possible that a connection exists here, and if this should 

 be so, this would indicate, as has been said above (p. 121) that the 

 Ozark region is to be included in the original home of the sub- 

 genus. C. monongalensis apparently is a representative form of C. 

 caro Units in southwestern Pennsylvania. 



The most puzzling distribution is offered by the remaining three 

 species, of which C. diogenes is the most widely distributed. This 

 species has an eastern and a western range on both sides of the 

 Allegheny Mountains. Apparently it has descended from the 

 mountains, that is to say, represents a more highly specialized 

 branch of the original mountain-loving chimney-builders. It has 

 descended into the Atlantic coast plain on the one side, and is 

 found from New Jersey to North Carolina (Cape Fear). On the 

 other side, it has descended westward, and is found from south- 

 western Pennsylvania over all the states north of the Ohio (also in 

 Kentucky) as far north as Minnesota and Wisconsin, westward to 

 Iowa (also reported from southwestern Wyoming and Colorado), 

 Kansas, and southward to Louisiana. This immense distribution 

 represents possibly the widest known range of any of the species 

 of crayfishes of the United States. The question remains open, 

 whether the eastern and western range of C. diogenes is actually 

 connected across the mountains. 



Of the other two species, C. ulilcri clearly is a local form of C. 

 diogenes, inhabiting the sea coast (brackish and salt marshes) in 

 Maryland. C. argillicola is morphologically very closely allied to 

 C. diogenes, and might be regarded, at least in Ohio, Michigan and 

 Canada, as a local form developed at the northern edge of the range 

 of C. diogenes. But the fact that C. argillicola is also found in cen- 

 tral and southern Indiana, in southern Illinois, and that it has been 

 reported from Mississippi and southern Texas (Victoria and Bra- 

 zoria), does not render this assumption probable : further investi- 

 gations of the range of these two species {diogenes and argillicola) 

 in the south and west are desirable, before their mutual geographic 

 relation can be ascertained. 



PROC AMER. PH1LOS. SOC. XLIV. iSo. I. PRINTED JULY 29, I905. 



