Plate IIIB 



Fip. 1. Crawfish chimney at Station T, Charlesion, III. Probably formed by Canibariis gracilis or 

 diogenes. (Pbotograph by T. L. Hankinson.) 



Fig". 2. General view at Station I, tf, showing numerous crawfish chimneys, probably formed by 

 Cambarus gracilis or diogenes. (Photog-raph by T. L. Hankinson.) 



