56 



U.S. NATIONAL MUSEUM BULLETIN 292 



Figure 7. — Petasmas of shrimps of the family Penaeidae {a-d, distal end viewed from right 

 side; e, entire structure in posterior view): a, Penaeus aztecus subtilis (carapace length 

 16.2 mm) from Jamaica {Albatross); b, P. hrasiliensis (cl 27.2 mm) from Golfo de Mor- 

 rosquillo, Colombia {Oregon station 4886); c, P. duorarum notialis (cl 21.3 mm) from 

 Bizeton, Haiti (W. Beebe); <f, P. schmitti (cl 23.5 mm), "cotype" from Kingston Bay, Ja- 

 maica; e, Xtphopeneus kroyeri (cl 13.2 ram) from Arroyo, Puerto Rico {Fish Hazvk). 



Family Atyidae 



Key to the Species 



1. Chelae of first and second pereiopods without tufts of long hairs at ends of 



fingers Xiphocaris elongata (p. 81) 



Chelae of first and second pereiopods with tufts of long hairs at ends of 

 fingers 2 



