CHAPTBE XV. 



FRESH-TSTATER CRXJSTACEANS. 



HE fresh-water Crayfish (Astacus fluviatilis) (Fig. 16S) 

 is a very interesting creature in an aquarium. The 

 aquarium, however, should not only be arranged 



especially for it, but it must also be given up to the animal's 



Fig. 165. Common River Crayfish (Astacus fluviatilis). 



use entirely. Any companion, except one of its own species, 

 it would be almost certain to either eat or hurt. A tank 

 intended for a pair of Crayfish ought to be about 2ft. long 

 by 1ft. or more broad. The bottom of this vessel should 



