THE PRAWNS, 269 
sition, are in fact the same. But, in the prawn, the abdomen 
is much larger in proportion to the cephalothorax; the 
Fie. 71. Palemon jamaicensis (about $ nat. size). A, female; 
B, fifth thoracic appendage of male. 
basal scale, or expodite of the antenna, is much larger; 
the external maxillipedes are longer, and differless from the 
succeeding thoracic appendages. The first pair of these, 
which answers to the forceps of the crayfish, is chelate, 
but it is very slender; the second pair, also chelate, is 
always larger than the first, and is sometimes exceedingly 
