390 Annals ov the Carnegie MusEUi\r. 



Remarks on these Species and Records of their Range. " 



I. Cambarus eartoni (Fabricius). The Common or Barton's 



Crawfish. 



This well-known species (for detailed description see Hagen, 1S70, 

 p. 75) is easily recognized by the characters given in the key. Aside 

 from the group-characters (form of male organs), the broad rostrum 

 without lateral teeth, and the wide areola distinguish it from any other 

 species of western Pennsylvania. 



It is found, as Williamson states, in springs and smaller brooks, 

 rarely in larger streams. Here it scoops out shallow holes under 

 stones, and very often makes quite deep burrows, piling up the mud, 

 sand, or gravel at the entrance in more or less regular piles, often 

 assuming the shape of "chimneys." Wherever there are favorable 

 localities in our region, this species is found, as it seems to be present 

 all over the state. The older records mention C. bartoni only from a 

 {q.\\ places in western Pennsylvania : Foxburg, Clarion county (Girard); 

 McKean county (Faxon, 1885); Westmoreland county (Faxon, 1898). 

 Williamson records it as common in Allegheny county. According 

 to the collections in the Carnegie Museum (made by E. B. William- 

 son, Dr. D. A. Atkinson, and the writer), it is found in the following 

 counties : Greene, Fayette, Somerset, Washington, Beaver, Allegheny, 

 Westmoreland, Butler, Clarion, Mercer, Crawford, Erie, McKean, 

 Potter. According to material preserved in the collections of the 

 Academy of Natural Sciences, Philadelphia, it is also found in Warren 

 county. This renders it a certainty that it is to be looked for every- 

 where in the western part of the state. In Erie county, the typical 

 C. bartoni is not very abundant, although present, and is largely re- 

 placed by the variety rohustus. (See below.) 



In the larger rivers this species is lacking, or found only occasion- 

 ally, and the writer has observed that in large rivers it is found chiefly, 

 where there are springs along the banks. These springs contain, in 

 summer, generally much cooler water, and it is in this cooler water 

 where C. bartoni is found, this species apparently disliking the warmer 

 water of the large streams. In the Allegheny and Ohio Rivers, below 

 Butler Junction in the northeastern corner of Allegheny county, it 

 is exceedingly rare, only stragglers occurring there. In the upper 

 Youghiogheny and Casselman Rivers, above Indian Creek in Fayette 

 county, this species is found regularly, although not very plentiful. 



