604 THE AMERICAN NATURALIST. [Vol. XXXVII. 



not been carefully described, but so far as known they are 

 essentially the same. That of C. diogcnes has a maximum 

 height of twelve inches, but is usually lower, is in shape, like a 

 truncated cone often somewhat higher than broad. The most 

 remarkable difference being that of chimneys two inches in diam- 

 eter and eight to eleven inches in height, described by Abbott, 

 who states that those found in meadows at a distance from run- 

 ning water were invariably broader and not so high as those 

 erected near running water. The chimney is composed of 

 pellets of clay firmly cemented together, owing to the moist 

 condition in which they are laid on, giving an irregular, nodular 

 appearance to the outside of the structure. This brief descrip- 

 tion applies to the more perfectly formed or typical chimney. 

 We will recur to this subject later, after the form of the burrow 

 has been mentioned. The actual process of construction has 

 been observed only once. 



As has been suggested above, where the habits of the differ- 

 ent forms was mentioned, the burrows are made at the time of 

 the drying up or the lowering of the body of water in which the 

 animals are found. At the edge the burrow may be a simple 

 shaft, a foot, more or less, in depth, ending below in a cistern- 

 shaped enlargement, in which the animal, usually only one but 

 sometimes two, is found. Farther back from the stream in 

 moist meadows where the burrows may have been begun at the 

 time of high water, the depth must necessarily be much greater 

 to reach soil water during the prolonged heat of summer. These 

 burrows are not uniform in structure but as yet data are lacking 

 for the determination of any plan, other than the one of reaching 

 water in the most direct manner. The presence of more than 

 one opening to the same burrow has often been noticed. They 

 are usually quite simple but occasionally are branched in various 

 ways. When many burrows occur in a limited area they may 

 easily become connected accidentally. Enlargements in the 

 shaft of the burrow have been noticed and attributed to the 



