1889.] ON SOME FEESHWATEK OSTBACODA AND COPEPODA. 59 



Order Copepoda. 

 Tribe Calanoidea. 

 Family Diaptomidae. 

 Gen. Diaptonius, Westwood. 

 1. Diaptomus orientalis, (Brady). 



(PI. VII, figs 12-16; PI. VIII, figs 1-4) 



Diaptomus orientalis, Brady 1. c, Linn. Soc. Journal. Zool. 

 Vol. XIX, p. 296, PI. XXXVII, figs. 21-26. 



Specific Characters. — Form of body rather robust, anterior 

 division in female oblong, tapered anteriorly, greatest width ex- 

 ceeding !/ 3 of the leDgth, terminal lobes broad, with outer 

 corner acute, inner obtuse. First caudal segment in female 

 about as long as the remaining part of the tail, nearly cylindric, 

 or but very little expanded at the base and without distinct 

 lateral spines; the 3 succeeding segments coalesced. Furcal 

 lobes rather broad in female, narrower in male. Anterior 

 antennas in female, when reflexed, reaching slightly beyond the 

 1st caudal segment; right antenna of male very much swollen 

 in the middle, antepenultimate joint produced anteriorly to a 

 st rong, slightly upturned spiniform process. Last pair of legs in 

 female with the inner ramus narrow cylindric, nearly as long 

 as 1st joint of outer ramus and terminating with 2 slender 

 spmes; terminal joint of latter ramus rather small and provided 

 with 2 unequal spines. Right leg of last pair in male robust, 

 mner ramus very small, 2nd joint of outer ramus broadly ovate, 

 s Pine of outer edge remote from the tip, apical claw sigmoid; 

 e t leg with outer ramus rather complicate in structure, having 

 2 digitiform processes and a rounded ciliate lamella. Colour of 

 emale m °i'e or less distinctly bluish green, anterior antennae 



