240 ON THE URITISH SPECIES OF ENTOMOSTKACA 



from two different localities in Ireland, — Lough Erne and Mel- 

 vin Lough, near Ballyshannon, have these distinctive characters 

 extremely well marked, the Lough Erne specimens being all 

 referable to D. Kahlbergensis, the Lough Melvin specimens to 

 D. galeata. 



Genus DACTYLUEA,* nov. gen. 



Eemale generally like Daphnia. In the male the antennule 

 has several short sensory filaments and one very long filament, 

 which is not prehensile or hooked, but has a densely ciliated or 

 pubescent apex (pi. YIII., fig. 2). The prehensile hook of 

 the first foot has an excrescent tooth at its base, and the caudal 

 lamina bears in front of the terminal unguis a finger-like lobe 

 (figs. 4, 5). The body generally is in both sexes pubescent, this 

 being especially evident in the antennae and caudal laminas. 



Under this genus will come Daphnia Atkinsoni, Baird, D. 

 magna, Strauss (= Sclicefferi, Baird), possibly D. psittacea, 

 Baird, and a species here for the first time described, Dactylura 

 pubescens. 



Dactylura pubescens, n. sp. (PL VIII., figs. 1-10, 20). 



Female. — Head well rounded in front (fig. 6), produced below 

 into a subacute but not very prominent beak, lower margin 

 slightly sinuated ; dorsal margin of the shell almost straight, 

 with a slight sinuation just behind the head; ventral margin 

 very strongly arched and prominent ; posterior extremity slightly 

 tapered, and produced a little below the dorsal line into a short 

 spine. The margins behind the middle of the shell are fringed 

 ■with numerous small, closely-set lancet-shaped spines, and, on a 

 line just internal to these and corresponding pretty nearly to 

 every third interspinous space, is a series of long setae (fig. Qa). 

 Antennules short and subconical, with widely truncated apices. 

 Antennae (fig. 7) short and densely pubescent. Abdominal pro- 

 cesses distinct, subequal, densely setifei'ous (fig. 8) ; post-abdomen 

 tapering up to the acute posterior extremity and bordered by a 



*^ ha.KTvX.o<i a finger, ovpa a tail. 



