1889.J OS SOME FRESHWATER OSTRACODA AND COPEPODA. 65 



and has the body on the whole rather more slender. The an- 

 terior division of the body is nearly fusiform, considerably 

 tapering both posteriorly and anteriorly. The lateral lobes of 

 the last segment are much smaller than in the female, forming 

 simple acute lappets not sharply defined at the base (see fig. 4). 

 The tail (ibid.) is very slender, about half as long as the ante- 

 rior division, narrow cylindric in form and almost of uniform 

 breadth throughout. It is moreover composed of no less than 

 5 distinctly defined segments, besides the furcal lobes. Of these 

 segments the 1st is very short, but a little broader than the 

 others. The 4 succeeding segments gradually diminish in length 

 in such manner, that the last is only half as long as the 2nd. 

 The furcal lobes are relatively narrower than in the female 

 and their setae less divergent. 



The anterior antenna? (see fig. 1) are relatively shorter 

 than in the female and are also borne in a somewhat different 

 manner, pointing a little obliquely forwards. Moreover they 

 are very assymetrical, the right being modified in a peculiar 

 manner to a prehensile organ, by the aid of which the female 

 is grasped during copulation. This antenna (fig. 2) exhibits 3 

 well-defined sections. The proximal section successively tapers 

 to the end and consists of about 13 or 14 joints, the outer of 

 which are densely crowded together and connected by very 

 oblique articulations so as to be very difficult to count exactly; 

 some of the outer joints are armed anteriorly with spines instead 

 of the usual seta?. The middle section is about of same length 

 *s the proximal but greatly dilated and of somewhat fusiform 

 SQ ape. It consists of 6 well defined joints, the 1st of which is 

 the smallest and produced anteriorly to a strong spiniform 

 process. A similar, though somewhat smaller spine is also found 

 on the 3rd joint, and on each of the 2 outer joints an appressed 

 acuminate process occurs, that of the last joint being connected 

 a highly chitinised and somewhat flexuous stripe. The 

 lnner ca ^ity of this section is traversed by an exceedingly 

 Powerful muscle joining the terminal part. The latter, which is 

 Very lovably articulated to the former section and admits by 



V *,Sel 8k . Forh 1889. No. 8 5 



