210 Bulletin Wisconsin Natural History Society [Vol. 13, No. 4 
retusa was very numerous throughout July and August. The 
slight drying out of the bog did not seem to affect them, as there 
were at least one — if not two — of these snails on every square 
inch of surface. About five o’clock in the afternoon they would 
crawl up on the grass or stems, and would remain there until 
morning. By nine o’clock next day every one of them was half 
buried in the mud, and remained so until afternoon. 
The crayfish, Cambarus diogenes, seemed to be the only animal 
which burrowed into the ground. Its chimneys (fig. 3) were a 
Fig. 3. The Chimney Hole of a Cray Fish, Cambarus diogenes. 
common sight in August above the holes which were sometimes 
five feet, or more in depth. A little dab of mud, or cap, was usu- 
ally fastened over the top of the burrow. When the owner left 
his burrow to seek the water, the cap was left off. Some of the 
larger crayfishes made their burrows back several feet on the 
shore, but the smaller ones built only under the surface of the 
water — only the cap of the “tower” showing above the surface. 
The frogs, which were very numerous, kept busy all day long 
in pursuit of crickets, small flies, and leaf hoppers which they ate 
