100 k REVISION OF THE BEITISH SPECIES OF 



branch ; terminal claw of the outer branch strongly falcate, and 

 delicately ciliated on the inner edge ; lateral spine attached near 

 the middle of the last joint, long, slender, and finely ciliated^ 

 Fifth foot of the left side (male) terminating in a snb-crescenti- 

 form hyaline lamina, the inner edge of which is delicately crenu- 

 lated. Length of male and female about 1*55 mm. 



I regret that I am unable, owing to the small number of 

 specimens obtained, and their imperfect preservation, to give a 

 more copious account of this species. My specimens were taken 

 in the year 1865, in two of the small peaty tarns of Connemara 

 (Lough Doon and Lough Nawheelan), nearly on the sea-level. 

 Amongst described species that to which they bear most re- 

 semblance is D. laciniatus, Lilljeborg. They come very near, 

 indeed, to this, but scarcely close enough to allow of my identi- 

 fying them with it. The species, however, requires further 

 investigation with the help of better specimens than those at 

 present available. 



5. Diaptomus hircus, n. sp. (PI. X., figs. 2-4). 



Female. — Seen from above the body is widest across the front, 

 thence tapering backwards to the hinder end of the thorax, 

 which is but little wider than the abdomen. The posterior 

 thoracic angles are mucronate but not very strongly produced. 

 The anterior antennae reach backwards as far as the posterior 

 end of the thorax. Inner branch of the fifth foot two-jointed, 

 more than half as long as the first joint of the outer branch, 

 its apex clothed with a fringe of minute cilia: second joint of 

 the outer branch ending in a stout, slightly curved claw, which 

 is finely ciliated on the concave margin; last joint bearing at its 

 apex a long, finely ciliated spine and one much smaller seta. 



Male. — Antepenultimate joint of the right anterior antenna 

 armed with a ploughshare-shaped process, which is nearly half 

 as long as the following joint, and has an obscurely fimbriated 

 free margin. Inner branch of the fifth foot of the left side very 

 small; outer branch slender, ending in two subequal finely 

 pectinated setae : the last joint of the protopodite has a finger- 

 like hyaline appendage on the inner margin, and there is a 



