I. '08. 



48 



P. tarda— couVd. \ 



3. Antennal scale (including 

 spine) rather more than hall' 

 the length of the carapace. 



4. Antennal scale evenly 

 convex throughout its length, 

 furnished apically with a long, 

 stout spine (fig. 9). 



5. Basus of second pereio- 

 pod with eight or nine ventral 

 spines (fig. 11). 



6. Telson narrow at its 

 apex, with a deep bifurcation 

 (fig. 10). 



P. princeps — cont'd. 



3. Antennal scale (including 

 spine) not more than half the 

 length of the carapace. 



4. Antennal scale strongly 

 convex in its distal third, fur- 

 nished apically with a small, 

 short spine (fig. 2). 



5. Basus of second pereio- 

 pod with at most four ventral 

 spines, sometimes unarmed 



i(tig. 7). 



6. Telson broader at its 

 apex , with a shallower bif ur- 



I cation (fig. 3). 



The mouth parts of the two species do not appear to offer 

 any important differential characters. 



Of the fifteen perfect specimens of P. princeps examined, 

 the largest two are males measuring 116 and 132 mm. in 

 length ; the others, none of which measure more than 75 mm., 

 show no trace of the additional stylet at the base of the endo- 

 pod of the second paii' of pleopods. 



In the largest specimen the rostrum (fig. 1) is dorsally 

 arched behind the apex, and in some of the smaller examples 

 traces of this feature are apparent (fig. 5). As will be seen 

 from the figures, the rostrum differs very considerably in 

 shape and forward extension ; in that of the smallest specimen 

 (37 mm.) no trace even of the sinuous anterior margin is ap- 

 jDarent. The specimens yield the follow^ing measurements 

 in mm. (cf. p. 41) : — 



. Total length. 



Carapace. ^ 



Abdomen. 



Antennal scale. ^ 



132 



48 



77 



20-5 



116 



36 



60 



16 



75 



24 



38-5 



11 



69 



21-5 



37-5 



10 



1 68-5 



21 



36 



10 



! 67 



20-5 



35 



10 



65 



20 



36 



10 



62 



19 



33 



9-5 



57 



17-5 



31-5 



8-.'^ 



55 



16 



29-5 



8 



53 



16-5 



29 



7-5 



52-5 



16 



29 



8 



51-5 



15-5 



27-5 



7-5 



i ' 47 



14-5 



25 



7 



37 



12 



20-5 



5 



1 Measured in mid-dorsal line. 



2 Including apical spine. 



