ORTMANN: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 469 
again further down. Thisis generally seen in the Ohio below Pittsburgh. Although 
the Ohio collects all the badly polluted streams of western Pennsylvania, it is itself 
not unfavorable to crawfish life. The best instance for this is the Cheat River. At 
Cheat Haven, Fayette County, this river is rather clear and teems with life, craw- 
fishes and Unionide being abundant. I was therefore astonished at the condition 
of this river at Parsons, Tucker County, West Virginia. The water there has a foul 
smell, and is utterly unfit for life, which is due to a wood-pulp mill just above Par- 
sons on Shavers Fork. Between Parsons and Cheat. Haven (about fifty miles) the 
water has improved so far that life is not only possible, but is abundant, only the 
blackish color of the water remaining as the last result of the contamination. 
We GIN, ISUISMNONR NG 
Only a few scattered notes have been published on the life-history of any of the 
American species of Cambarus, and some of them are rather doubtful. The most 
complete account is that given by Andrews (1904) on the breeding habits of C. limo- 
sus, but even this comprises only a small part of the life-history, and moreover, as 
may be seen below, is in part rendered unreliable by the fact that the observations 
were not made in the field, but in the laboratory. 
My own observations have been almost exclusively made in the field, and were 
only occasionally supplemented, or rather confirmed, in the laboratory. Since it 
was my object from the beginning to watch the behavior of the crawfishes under 
natural conditions, laboratory-work could not be depended upon, unless controlled 
by field-work, and thus the former was neglected altogether. 
With the exception of January and February,” my work in Pennsylvania extends 
over the whole year, thus including all seasons. ‘The results are rather satisfactory, 
and I am able to give a complete account of the seasonal life of no less than four 
species, and by comparison with these the life-history of the other species of this state 
may be inferred. Of course I have not been able to solve all questions. For 
instance the question of the frequency of moulting in one and the same individual 
remains open, since it can only be settled by observing the same individual contin- 
uously ; but this is impossible in the field. Nevertheless I have found means to 
elucidate this question in other ways, although not with absolute accuracy. 
The most numerous and most complete records I possess refer to the common 
river-species of western Pennsylvania, C. obscwrus, and of this I shall first give an 
account. 
§§From New Jersey I possess observations made even in January and February and referring to C. blandingi, C. 
limosus, and C. bartoni. ; 
