162 



THE HON. PAUL A. METHUEX ON 



[Feb. 1 



inner margin three bristles are found, of which the proximal is 

 setaceous ; between this bristle and the joint of the first and 

 second segments there is a close-set row of fine stiff bristles, 

 in the form of a long comb, placed just internal to the inner 

 margin of the joint which is itself partly fringed with fine hairs ; 

 occupying the centre of the surface of this same segment is a mass 

 of fine long hairs set in the long axis of the same and occupying 

 about a third of its length. 



The thoracic limbs (figs. 53 & 54) used for swimming are like those 

 of a typical Diaptomus ; but the modified sixth pair is sufficient 

 to show the marked aberrancy of this species from Diaptoimis or 



Text-fig. 11. 



E-xofi 



Exop 



Exop. 



Cushions 



Cushions 



Ba3. 



Sixth Thoracic Appendages of (A) Diaptomus castor (after Schmeil) ; (B) 

 Metadiaptomus ; (C) Adiaptomus natalensis (after Cooper). P. possibly 

 indicates remains of endopodite. 



any other Centropagid genus described. For convenience sake, 

 the sixth pair of thoracic appendages of the male of Diaptomus 

 castor, of Adiaptomus natalensis, and of the new species now 

 under discussion are here figured side by side for comparison, 

 since it is thought that the character of these limbs is of the 

 greatest importance for classification {vide text-fig. 11.4, B, C). 

 The whole organ is seen to consist of a pair of asymmetrical limbs, 



