528 



CRUSTACEA MALACOSTRACA. 



A long compressed rostrum is usually present. First antenna 

 usually bears a stylocerite. Second antenna usually with a 



a 



Fio. 323. Larvae of Penaeus. (From Claus, after Fritz Miiller.) a, nauplius form seen from the 

 dorsal surface, b, metanauplius stage seen from the left side ; c, zoaea stage ; A', A" first 

 andsecond antennae ; Gl sixth and seventh pairs of appendages (first and second maxillipeds) ; 

 Mdf mandiiiulnr palp of nauplius ; MX' anterior maxillae ; MX" posterior maxillae ; Mxf, 

 Mj-f" first and second maxillipeds ; eyes. 



large flat scale (exopodite). Thoracic legs slender, abdominal 

 legs powerful swimming appendages. 



Tribe 1. PENAEIDEA. 



Gills dendrobranchiate. The 1st abdominal segment not overlapped 

 by the 2nd, 1st antenna usually with a stylocerite. The 3rd and frequently 



