56 CHAPTERS ON THE NATURAL HISTORY 



the pellets, to a great extent, fused together, and the outer sur- 

 face of the chimney or mound had simply a nodulated appear- 

 ance, and the structure was much longer in drying out. Various 

 different phases were to be seen between these two extremes. I 

 tried to dig to the bottom of one of these passages, but owing to 

 the nature of things in these wet lowlands of Louisiana, this was 

 not feasible, for abundance of water was soon reached, and to 

 follow the course of the passage was not possible by any ordinary 

 means. 



Often I have seen the crayfish in these abodes, and have cap- 

 tured them there, and I once caught one in the act of sealing in 

 the top of its chimney, but I have never seen them at work dur- 

 ing the actual building process. Mr. Balph Tarr, who has writ- 

 ten upon this subject (Nature, vol. xxx., p. 27), believes that the 

 chimneys result from the excavation of the burrow, without im- 

 plying design on the part of the crayfish. This is also the opin- 

 ion entertained by myself, while Dr. C. C. Abbott holds the con- 

 verse view, as does also his nephew, Mr. Jos. De B. Abbott, who 

 has, by the aid of the light of a candle at night, seen the crays 

 engaged in building their chimneys. 



A few years ago, in Southern Maryland, I found the chimney 

 of a Barton's crayfish. It was nine and a half inches in height, 

 very smooth inside, and with the pellets distinctly individual- 

 ized outside. Many of these were piled up about the base, 

 and forty-two of them had rolled out beyond the latter. It was 

 erected on level ground with a firm turf, and about ten feet 

 from a small stream. In attempting to follow down the 

 burrow, water was met with at fifteen inches, but the bur- 

 row 7 was still followed for twenty-seven inches more, when 

 it passed between two large rocks, too large to move, and so 

 rendered further progress out of the question. In a few nights 

 the cray abandoned this site, and burrowed again close at hand. 

 In the same vicinity, right on the bank of the streamlet, I 

 opened another; it only passed down eleven inches, when 

 it terminated in a chamber about as big as my two fists, and 

 placed at the side. It was below the water level, and contained a 

 fine living specimen of C. diogenes. Beyond this was a low mound 

 in wetter soil. Unlike the other two, the top of this one was 

 sealed over, and the pellets nearly all run together. Upon tak- 

 ing this one up in my hand (it is before me now 7 as I write), I 

 found the sealing-in was very thorough, and the top as thick as 



