164 KANSAS UNIVERSITY SCIENCE BULLETIN. 



gravelly ground and the chimneys were, naturally, of the same 

 material, instead of clay, as is usually the case. The descrip- 

 tion of the exterior of the chimney, composed of irregularly ar- 

 ranged nodules of clay, and the inside a smooth opening of the 

 same diameter as the burrow, is much the same in all the pa- 

 pers. Of the external form of the chimneys of other burrow- 

 ing species little has been written, but so far as essentials of 

 construction and general appearance are concerned they may be 

 assumed to be very similar. 



It would be useless to go into a detailed enumeration of the 

 different forms of burrows described, since, until by more ex- 

 tensive observations than have yet been made the contrary is 

 shown to be the case, the amount of regularity, beyond the 

 necessary similarity of form which characterizes the simple 

 burrows, may not be supposed to be very great. It seems 

 quite evident that the burrows are made as the level of the 

 water lowers, those near the edge having a depth of but a few 

 inches, while those farther back may be some feet deep. A 

 cistern-shaped opening, containing water, is described at the 

 bottom, while enlargements at various intervals in the burrows 

 have been noted and probably correctly explained as the origi- 

 nal termini of the burrow which has been projected deeper 

 upon the lowering of the water in the soil, but in the case of 

 the burrows of C. carolinus, as observed by Williamson, this 

 interpretation does not seem to hold, and may not in all cases 

 with C. diogenes or the other forms. The burrows have usu- 

 ally been described as separate, but when they are very close 

 together they are not unlikely to become connected. The pres- 

 ence of more than one opening to the same burrow in many 

 cases seems established. Sometimes one and sometimes two 

 individuals are found in a burrow. 



The purpose and method of construction of the "chimney," 

 as it has been aptly called, have called forth considerable discus- 

 sion, some maintaining that a structure of such regularity of 

 construction must have some purpose ; others concluding that 

 the building of a chimney simply represents the safest and 

 most convenient method of disposing of the material obtained 

 in excavating the burrow. The latter view seems to have by 

 far the greater amount of evidence in its favor. The purpose 

 of sealing the burrows needs more study. The method by 



