12(11) Antennules flattened; cervical sulcus present; 

 sixth abdominal segment short and slightly 



curved Solenocera 



Antennules round ; cervical sulcus absent ; sixth ab- 

 dominal segment long and straight, .Parapenaeus 



13(11) Rostrum longer than eye Xiphopeneus 



Rostrum shorter than eye 14 



14(13) First abdominal segment with anteromedian 

 spine on dorsal surface; sixth abdominal segment 



short Sicyonia 



First abdominal segment without anteromedian 

 spine on dorsal surface; sixth abdominal segment 

 elongate Trachypeneus 



Figure 7. — Penaeid postlarvae: a, Parapenatus postlarva, 8.0 mm.; b, Penaeus postlarva, 6.0 mm.; c, Penaeus postlarva, 

 15.0 mm.; d, Sicyonia postlarva, 5.0 mm.; e, Sicyonia postlarva, 14.0 mm.;/, Solenocera postlarva, 7.0 mm.; g, Trachy- 

 peneus postlarva, 6.0 mm.; h, Trachypeneus postlarva, 10.0 mm.; i, Trachypeneus postlarva, 25.0 mm.; j, Xiphopeneus 

 postlarva, 6.0 mm.; k, Xiphopeneus postlarva, 7.5 mm.; m, Xiphopeneus postlarva, 12.0 mm.; I, Tip of telson. 



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U.S. FISH AND WILDLIFE SERVICE 



