20 



10 



20 



10 



20 



10 



i/i 



20 



10 



10 



20 



10 



C.I. 9-15 



N = 16 



C.I. 16-22 



N = 42 



C.I. 23-29 



N=46 



C.I. 30-36 



N = 44 



C.I. 37-43 



N = ll 



C.I. 44-58 



N = 14 



5.0 

 K, 



6.0 



7.0 



8.0 



Vs 



I 



■^So^" 



1 mm. 



1 I 



Figure 57. — Pcnacus (If.) 

 aztecus suMUis P^rez 

 Farfante. Petasma, lat- 

 eral view, S 34 mm. 

 C.I., off Puuta Gallinas, 

 Departameuto de la Gua- 

 jira, Colombia. 



FiGUBE 56. — Frequency distribution of keel-sulcus (K/S) 

 values (both sexes included) in Penaeus (M.) aztecus 

 siMilis Perez Farfante of different size classes from 

 the Gulf "of Paria to Camocim, Brazil. 



Distribution and Morphological Variations 



P. a. mbtilis range.s from Cuba through the An- 

 tilles and from Honduras throughout the Carib- 

 bean Coast of Central and South America and the 

 Atlantic Coast of South America to at least Cabo 

 Frio, Brazil. Burkenroad (1939) reported and il- 

 lustrated specimens of this subspecies from "Rio 

 de Janeiro" (fig. 49). The distribution of the dark 

 shrimp is far from uniform, because population 



WESTERN ATLANTIC SHRIMPS OF GENUS PEXAEVS 



5mm. 



Figure 58. — Penaeus (J/.) aztecus subtiUs P4rez Farfante. 

 Thelycum. 9 45.5 mm. c.l., off Isere Point, French 

 Guiana. 



551 



