^EESHWATER PRAWNS. 



329 



are terminated b}^ great chelae, not unlike those of the 

 crayfishes. Hence these fluviatile prawns (known in 

 many places b}^ the name of " Cammarons ") are not 

 unfrequently confounded with true crayfishes; though 



Fig. 79. Palccmon jamoiceiuis (about f nat. size). A, female; 

 B, fifth thoracic appendage of male. 



the fact that there are only three pair of ordinary legs 

 behind the largest, forceps-like pair, is sufficient at once 

 to distinguish them from any of the Astaciche. 



Species of these large - clawed prawns live in the 



