IO 



the carapace. 



P. tenellus. 

 10. Carapace with setae at the upper, anterior part. 



P. cornutus. 



D. Tooth at the anterior, inferior angle of the carapace. Second 



joint of the first and second pereiopoda unispinose. Dorsal 



median kiel is found from the second somite of the pleon 



i backwards. Lateral spines on the tail segment. Seminal 



, receptacle consists of two entirely separate cavities. Shell 



thickly beset with setae. 



d. Petasma bilaterally symmetrical. No spine between 

 the second pair of pereiopoda. 



ii. . Lateral spines of the tail segment very minute, 

 hardly visible with naked eyes. 



P. airvirostris. 



e. Petasma not bilaterally symmetrical. Paired spines 

 between the second pereiopoda. 3 pairs of movable 

 spines and 1 pair of not-movable spines on the tail 

 segment. 



12. Rostrum broad and short, slightly longer than the 

 eyes. 



P. lamellatiis. 



1 3. Sixth pleonic segment and the tail segment long, 

 subequal in length to that of the sixth pleopoda. 

 First joint of the fourth pereiopoda enlarged. 



P. velutimis. 



