FRESHWATER PRAWNS. 329 
are terminated by great chele, 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; though 
Fie. 79. Palemon jamaicensis (about § 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 Astacide. 
Species of these large-clawed prawns live in the 
