24 G. O. SARS. [SEC. ARC. EXP. FRAM 



scarcely exceeding half the length of the cephalic segment and rather 

 densely setiferous, 1st joint much the largest, 2nd joint nearly as long 

 as the 2 succeeding joints combined, terminal part rather narrow and 

 about half the length of the proximal one. Posterior antennae and 

 oral parts of the structure characteristic of the genus. Posterior maxilli- 

 peds, as in the type species much less robust than in the genus Tha- 

 lestris, the hand being narrow fusiform in shape, with the palmar 

 edge nearly straight. 1st pair of legs with both rami rather slender 

 and distinctly prehensile, the outer one a little longer than the inner, 

 and having the 2nd joint long and slender, last joint small and armed 

 with 2 strong subequal claws accompanied by a slender seta, outer 

 edge of the joint moreover carrying 2 comparatively small spines; inner 

 ramus with the outer 2 joints very short, the last one armed with a 

 long slightly curved claw, outside which is a much thinner setiform 

 spine. Natatory legs of normal structure. Last pair of legs very largely 

 developed, though scarcely to such an extent as in the type species, 

 extending about to the end of the 2nd caudal segment, both joints pro- 

 nouncedly foliaceous, the distal one oblong oval in form and provided 

 with 4 thickish, coarsely ciliated setae, 3 of which are attached to the 

 outer edge, the 4th to the inner edge near the end, the tip itself carry- 

 ing 2 unequal very thin, hair-like bristles; inner expansion of proximal 

 joint extending as far as the distal joint and broadly rounded at the 

 end, marginal setae 5 in number, the innermost not far remote from 

 the others. 



Male considerably smaller than female and exhibiting the usual 

 sexual differences. 1st pair of legs with the spine _attached to the inner 

 corner of the 2nd basal joint falciform, incurved. Inner ramus of 2nd 

 pair of legs transformed in a similar manner to that in the type 

 species. Last pair of legs much smaller than in female, with the inner 

 expansion of proximal joint quite short, and provided with only 3 setae. 



Length of adult female 1.30 mm. 



Remarks. This form has been described and figured, though 



somewhat imperfectly, by TH. SCOTT in the above-quoted paper as a 

 species of the genus Thalestris. According to the general form of the 

 body, the shape of the rostrum, the structure of the posterior maxilli- 

 peds and the great development of the last pair of legs, it is undoubt- 

 edly referable to the genus Phyllothalestris, as defined by the present 

 author in his account of the Norwegian Harpacticoida. It is distinguished 

 from the type species, P. mysis GLAUS, by a number of well-marked 

 characters pointed out in the above diagnosis. 



