THE PRAWNS. 



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sition, are in fact the same. But, in the prawn, the abdomen 

 is much larger in proportion to the cephalothorax ; the 



Fia. 71. PnlcBmon jnvinwpn.vs (about 4 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 differ less from the 

 succeeding thoracic appendages. The first pair of these, 

 which answers to the forceps of the crayfish, is chelate, 

 but it is v^y^ slender ; the second pau% also chelate, is 

 always larger than the first, and is sometimes exceedingly 

 13 



