196 



outer ramus scarcely half as long, and carrying 4 short setae, 3 of which belong 

 to the last joint. 1st pair of legs with the outer ramus about the length of the 

 1st joint of the inner, last joint somewhat larger than the preceding one, and 

 armed with 2 spines and 2 geniculated setse; inner ramus twice as long as the 

 outer and very slender, 1st joint about the length of the other 2 combined, the 

 latter somewhat unequal, the terminal one being much the longer and very nar- 

 row linear, carrying on the tip a slender denticulated spine, a long seta, and a 

 small hair-like bristle. Natatory legs exceedingly slender, inner ramus of the 2 

 anterior pairs extending considerably beyond the 2nd joint of the outer, that of 

 4th pair to about the middle of that joint. Last pair of legs with the distal 

 joint narrow oblong in form, and armed with 5 spines, 3 on the outer edge, one 

 very small one on the inner edge near the end, and one very long apical one; inner 

 expansion of proximal joint broadly rounded, and not extending to the middle of 

 the distal joint, marginal spines 5 in number and somewhat unequal. Ovisac 

 short and rounded, sub-globose in form, never extending beyond the end of the 

 urosome. Spermatophore attached to the genital opening very large, sabre-like, 

 and often of a very dark brownish colour. 



Male not much smaller than female and easily recognizable by the pre- 

 hensile anterior antennae and the complete division of the anterior caudal segment. 

 1st pair of legs of exactly the same structure as in the female. Inner ramus 

 of all the 3 succeeding (natatory) pairs conspicuously transformed, that of 2nd 

 pair rather slender, with the outer 2 joints imperfectly defined, the last one armed 

 inside with a short deflexed spine, and carrying on the somewhat obliquely rounded 

 extremity 3 setse, the outermost of which is much elongated; that of 3rd pair 

 considerably shortened, middle joint produced at the end inside to a strong de- 

 flexed mucroniform process, last joint short, oval in form, and tipped with a small 

 bristle; that of 4th pair with the distal joint produced at the end outside to a 

 short spiniform projection, inside which 3 closely-set, long, curved and somewhat 

 spiniform setae are attached. Last pair of legs smaller than in female, distal joint 

 of a similar shape, but provided inside near the base with an additional slender 

 spine; inner expansion of proximal joint quite short, and provided with only 2 

 unequal spines. Genital lobes armed with 2 spines and a hair-like bristle. 



Colour somewhat variable, in some cases yellowish green, in others more 

 reddish; that of male more generally of the last-named colour. 



Length of adult female about 1 mm. 



Remarks. It is very probable, that the Cyclops minutus of 0. Fr. Miiller 

 refers to the ptesent species, and that thus the identification made by earlier 

 authors is quite correct. But in any case the name minutus would be very inap- 



