FEESHWATER PRAWNS. 



329 



are terminated by great chelae, not unlike those of the 

 crayfishes. Hence these fluviatile prawns (known in 

 many places by the name of " Cammarons ") are not 

 unfrequently confounded with true crayfishes; tliough 



Fig. 79. Palmmon jamaicensis (about f nat. size). A, female; 

 B, fifth thoracic appendage of male. 



the fact tliat there are only three pair of ordinary legs 

 behind the largest, forceps-hke pair, is sufiEicient at once 

 to distinguish them from any of the Astacidce. 



Species of these large - clawed prawns live in the 



