Oscar Sund. [Nr. 6 



Pasiphæa principalis, nomen novum. 



P. tctrda Nordgaard, 1905. 

 P. tarda H. J. Hansen, 1908. 

 P. princeps Kemp., 1910. 

 P. tarda Stephensen, 1912. 



This species was confounded with "P. tarda" (really P. multi- 

 dendata) so far as regards the specimens caught on this side of 

 the Atlantic, until Kemp (1910) made clear the differences between 







-f 



Pasiphæa multidentata, measured 



by Snnd. 















s — tarda, — 



— 











• 



— principalis, — 



- — 











o 





- Kemp. 







50 

 45 

 AQ 



% 

 % 



% 





Of+OO + 



o o + 

 o#-« O +--(-+• 



+ -t- •+• «o 



oo o++ + • 



O »0 

 00 



o + 



• 



• o • 



o • 



• 



* 



• 

 

 oO 





C 



) mn 



'■..5 



10 15 20 25 50 



35 40 45 



50 



55 O 



Fig. 2. Sc. = length of scaphocerite (antennal plate}, Cr. = median length of 



carapace. The ordinates represent the ratio Sc : Cr as % of Cr, the ahscissae 



represent Cr. No evidense of specific difference is shown in this ratio. Each 



spot in the diagram represents one measured specimen. 



them. I cannot however agree with Kemp in regarding the ratios 

 between the length of the antennal scale and that of the carapace, 

 and between the length of the carapace that of the abdomen as 

 distinctive of the two species. In fact, as will be seen from the 

 accompanying diagrams figs 2 and 3, both these ratios vary ac- 

 cording to size. Moreover the second ratio especially is very difficult 

 to determine with certainty, at it is impossible to stretch the abdomen 

 of specimens preserved in alcohol quite straight. But if we only 

 consider the adult individuals it holds true that the antennal scale 

 is shorter and the abdomen longer in proportion to the length of 

 the carapace in P. principalis than in P. multidendata, because 

 the last named species is adult when perhaps only two-thirds the 

 length of P. principalis. 



