104 KANSAS UNIVERSITY SCIENCE BULLETIN. 



inches across at the bottom, was found to contain in this cham- 

 ber a large first-form male and a somewhat smaller female. 

 The burrow had apparently been carefully sealed by the ani- 

 mals. Some time later the pond was again examined, and no 

 crayfish were found, but numbers of chimneys in various stages 

 of disintegration were seen. In another pond containing more 

 water, the crayfish were very abundant at about the same time. 

 About the middle of October the locality was again visited ; 

 some of the burrows had chimneys, others were simply open at 

 the top — probably old burrows whose chimneys had been dis- 

 integrated by the weather. The form of the chimney varies 

 greatly. Sometimes the mud appears to be just thrown out on 

 one side, tlien, after a considerable amount of material has ac- 

 cumulated, the remainder is thrown out wherever convenient, 

 forming an irregular circular mound one to three inches high 

 and six to nine inches across ; sometimes a long ridge with a 

 shaft in the middle is formed, the material being thrown out in 

 two directions ; while again the work sometimes seems to be 

 discontinued before so much mud is removed to make it in- 

 convenient to throw it all to one side, thus forming a crescent- 

 shaped pile. 



The largest chimneys noticed were about five inches high and 

 three inches in diameter at the top. These were sometimes 

 much inclined from the perpendicular. He concludes that for 

 this species the theory of Tarr ('84) and Schufeldt ('97), that 

 the chimney is simply material ejected from the burrow and not 

 the result of a design on the part of the animal, is correct. Chim- 

 neys in presumably the same sort of localit}^ as those described 

 by Abbott ('84) were examined, and he could not convince 

 himself that anything other than the easiest method of dis- 

 posing of material could have prompted the animal to build a 

 chimney-like structure. The mud is brought up in such a moist 

 condition that there would be little danger of the pellets rolling 

 down, as suggested by Abbott ('84). The amount of mud 

 brought up sometimes is very considerable, amounting, in some 

 cases, to as much as 200 cubic inches. The accidental sealing 

 of the burrow would seem impossible. The opening through 

 the chimney seems to be left till the last, when it is filled from 

 the top, or near the top, to almost the level of the ground, 

 where the shaft has a concave, hemispherical end, which is not 



