418 MEMOIRS OF THE CARNEGIE MUSEUM 
b. Shape of the burrows. (See Pl. XL, Figs. 8 and 9, Pl. XLI.) 
The burrows of these species (and also of C. bartoni) are to a certain degree alike, 
although they are very variable in depth and shape, so that there is very little uni- 
formity. Only a few features are common to them. From the more or less dry 
surface they go down to the groundwater, where there is generally a kind of a pocket 
or widened chamber (Pl. XLI, Figs. 5 and 6). The width of the hole corresponds 
to the size of its inhabitants. It seems that one and the same individual perma- 
nently uses the same hole, although one and the same hole may be occupied by dif- 
ferent individuals in succession, for an old abandoned hole may be occupied by a 
young specimen. This happens chiefly in localities where the holes are much 
crowded. There are places where the ground is fairly honeycombed with them,** and 
under such conditions a new hole may interfere with an old one, when a young 
specimen after attaining the proper size begins to build its own burrow, as it invari- 
ably does. If the old hole is abandoned the young specimen may take advantage 
of it, while in the alternative case, a fight ensues which ends in the expulsion or de- 
struction of the weaker. 
Each hole is always occupied by one individual only, with two exceptions. The 
first is the case of mating couples, when one adult male of the first form and one 
female are found in one and the same hole. The second is when the young of a 
certain size are associated with the mother in the hole of the latter. 
The holes have all manner of shapes (see Pl. XL, and Pl. XLI). They may con- 
sist of a single shaft only, or may be more complex, branching off in various direc- 
tions, and may have more than one opening at the surface. The chamber may be 
well marked or indistinct, and there may be several chambers. The chambers may 
be simple widenings of the hole, or may form side pockets. The direction of the 
descending shaft is rarely more or less vertical, and if vertical in the upper part, it 
generally soon assumes a slanting direction, and sometimes it is irregularly spiral. 
Shorter or longer branches . may go off at the sides, and these may end blindly or 
may ascend to the surface. At the bottom side-branches may be absent, or may be 
developed to a considerable extent, running either horizontally or vertically. On 
steep hillsides, or along the banks of ditches, the general direction of the burrows is 
very often horizontal, the outward opening being lateral (Pl. XI, Figs. 2, 3, 7). 
The depth of the holes depends on the distance of the level of the groundwater 
%° I have seen this on the largest scale in the case of (. carolinus in the valley of Upper Decker’s Creek near Reedsville, 
Preston County, W. Va. The whole valley, for two or three miles, offers favorable conditions for this species, and 
thousands of chimneys may be seen everywhere, coming up even between the railroad ties of the Morgantown & King- 
wood Railroad. 
