170 UPLAND AND MEADOW. 



point of view: of all the burrowings of this crayfish 

 that I have examined, or that I have had examined by 

 others, every one terminated in a little pool of water, 

 scarcely big enough to let " Diogenes" turn around ; and 

 some of his burrows are on tide-water flats, which are 

 alternately flooded and exposed. Why, then, should a 

 passing shower induce the crayfish to close the opening 

 of its chimney ? 



In Ifature, No. 726 (June 5, 1884), Mr. Ralph S. 

 Tarr gives an interesting account of his observations of 

 the chimney-building crayfish {Camharua Diogenes). His 

 conclusions and my own with reference to this crusta- 

 cean tally, except upon one point. Mr. Tarr remarks, 

 " I do not think the chimney is a necessary part of the 

 nest, but simply the result of digging." On the con- 

 trary, I am convinced that the crayfish huilda his chim- 

 ney or tower; that he often studies the locality with 

 care and builds to suit the chosen site. My reasons for 

 this conclusion are: That a large series observed during 

 the present year were so placed on a steeply sloping 

 bank of a ditch, that if the materials of which the 

 towers were composed had been simply rejected matter 

 derived from tunnelling, then it could have been rolled 

 into the ditch without trouble; while in fact an artistic 

 tower, only two inches in diameter and varying from 

 eight to eleven inches in height, was erected ; and in 

 several instances the base of the tower was specially pro- 

 vided for by having the ground levelled and smoothed 

 before the foundation masses of puddled clay were put 

 in position. Of a series of forty towers built by the 

 Camharus Diogenes that I observed on the banks of a 



