185 



122. Stenhelia palustris (Brady). 



(PI. CXXII). 

 Delavalia palustris, Brady, Monogr. Brit. Copepoda, Vol. II, p. 43, PL 4, figs. 1 8. 



Specific Characters. Female. Body, as in the 3 preceding species gra- 

 dually tapered behind, hut somewhat less robust, with the segments more sharply 

 marked of from each other. Rostrum with the apical part less sharply defined 

 and somewhat retuse at the tip. Urosome much shorter than the anterior division, 

 anal segment coarsely spinulose at the hind edge ventrally and laterally. Caudal 

 rami exceeding in length the anal segment, and somewhat constricted at the base, 

 apical setae comparatively shorter than in the other species and more divergent. 

 Anterior antennae with the last 3 joints imperfectly defined, otherwise of the usual 

 structure. Posterior antennae, mandibles, maxillae and anterior maxillipeds scarcely 

 different from those parts in the 3 preceding species. Posterior maxillipeds 

 very delicate and not at all prehensile, the propodal joint being lamelliform, and 

 the dactylus replaced by a simple seta. 1st pair of legs with the outer ramus 

 coarsely spinulose outside, middle joint with a well-developed seta inside, last 

 joint a little longer and obliquely truncated at the tip, carrying 2 strong spines 

 and 2 unequal setae, neither of which is geniculated; inner ramus scarcely as long 

 as the outer, and consisting of only 2 joints, the 1st provided inside, as in the 

 other species, with a strong plumose seta, last joint longer and narrower than 

 the 1st, and without any seta inside, outer edge clothed with 2 oblique rows of 

 spinules, tip produced outside to a short dentiform point, inside which a slender 

 denticulated spine and a somewhat shorter seta are attached. Natatory legs 

 strongly built and of normal structure. Last pair of legs with the distal joint 

 almost quadrangular in shape, tip obtusely rounded, and carrying 6 not much 

 elongated setae, proximal joint not expanded inside, and confluent with that of 

 the other side, the posterior edge carrying 2 unequal setae at a short distance 

 from the insertion of the distal joint, and farther inwards an extremely small 

 hooked spinule and a short bristle. Ovisacs very large and divergent. 



Male with the inner ramus of 2nd pair of legs biarticulate, distal joint 

 oblong oval in form, scarcely tapering behind, and terminating in a short denti- 

 form point, outside which quite a short curved seta is attached, coarsely ciliated 

 in the middle, inner edge carrying in front of the middle 2 unequal setae and near 

 the end a very coarse deflexed spine, bifid at the tip, and having inside a few 

 spinules. Last pair of legs quite rudimentary, being reduced to a narrow trans- 

 verse plate carrying on each side a strong spine and 3 simple setae. Genital 

 lobes somewhat unequal, each with 3 hair-like bristles. 



