416 MEMOIRS OF THE CARNEGIE MUSEUM 
Since those parts of the stream which are inhabited by C. bartoni robustus are 
always well supplied with water, this form does not need to make extensive bur- 
rows, and I have never observed regular chimneys.” 
The ecological conditions under which C. bartoni occurs were to some extent 
previously known. Goodman (1833 (1842), p. 293) gives a good account of them” 
as observed in small streams near Philadelphia. According to Abbott (1873) it is 
found near Trenton, N. J., burrowing in the muddy banks of ditches and small 
streams, rarely of the river (Delaware). This, however, is not the usual condition, 
as we have seen above. Faxon (1885a, p. 63) says that it prefers cooler waters of 
mountain regions or uplands, living under the stones in clear streams and in 
springs, which is the usual condition under which it is found in this state. How- 
ever, that there are variations in its habitat, occasioned by exceptional conditions, 
is seen from the case mentioned above from the state of Ohio, from Abbott’s account, 
and from the observations of Dr. J. Sloan as reported by Faxon (J. c.), according to 
which, in southern Indiana, it is found in ponds and still water, not in running 
streams. ‘This is, however, not always the case in Indiana, since, according to Hay 
(1896, p. 489) it is found in “springs and streams of clear running water, where it 
hides under stones or digs short burrows into the banks.” 
3. The Burrowing Species. 
Cambarus carolinus, Cambarus monongalensis, Cambarus diogenes. 
a. General habitat. 
The burrowing species are always found at a certain distance from open water, 
although often in close proximity to streams, ditches, or ponds; but never, under 
normal conditions, in them. Exceptions are very rare, and only accidental, and 
found chiefly in the case of young individuals which have not settled down perma- 
nently, or of individuals which have been disturbed.** These species, however, 
always depend on the presence of water, but it is the groundwater which is inhabited 
% Shufeldt (1896, p. 27) figures a chimney of C. bartoni rubustus from near Washington, D.C. Why Shufeldt attrib- 
utes this chimney to this form, I do not understand. He says that he studied burrows near Washington, ‘‘many of 
these were of C. diogenes, others were of C, bartoni robustus, which I found abundant in Montgomery County, Md.”’ 
The specimen which built the chimney figured was not taken by Shufeldt, and he says that in the vicinity another bur- 
Tow was opened which contained a C. diogenes. According to the description of the hole belonging to the chimney, it is 
too deep and complex to belong to C. bartoni, and I do not see any reason for not regarding it as belonging to C. diogenes. 
* The crawfish hole, eight to ten inches deep, with a wider chamber at the end, under stones in a small stream, 
with the opening in the water, undoubtedly belongs to this species. 
*'4 case where young specimens of C. diogenes were found in numbers in open water by Dr. D. A. Atkinson will be 
discussed below. (See V.) This case is also to be regarded as exceptional. 
