| OCR Text |
Show 124 DR. G. STEWARDSON BRADY ON [May 17, collection, agreeing down to the minutest details with British specimens. E ctocyclops, n o v. g en. Like Cyclops except that the mandibles, maxillae, and maxillipeds are less fully developed and are very indistinctly jointed, the posterior antenna bears a very stout ciliated seta on the posterior margin, and the terminal joints of the rami of the swimming-feet are scarcely at all elongated. E ctocyclops ru b e scen s , n. sp. (Plate VI. figs. 19-20; Plate VII. figs. 21-27.) Female. Body depressed, rather robust (fig. 19); cephalothoracic segments not produced laterally; abdominal segments short and stout, posterior margin of the last segment pectinated, furcal segments not much longer than broad; principal tail-setae marginally aculeated, the innermost nearly equalling three-fourths of the length of the body ; ovisacs large and adpressed. Anten-nules (fig. 20) ten-jointed, much shorter than the first cephalothoracic segment, and rather densely setiferous ; antennas (fig. 21) robust, anterior margin fringed towards the base with numerous short setae, penultimate joint with about six larger setae, terminal joint with several longer setae; on the posterior margin rising from the base of the second joint is a very long and stout ciliated appendage. Mandibles bearing a rudimentary palp consisting of three very small setae; maxillae (fig. 22) not much different from those of Cyclops ; anterior and posterior maxillipeds (figs. 23, 24) small, stout, and indistinctly jointed, the marginal curved teeth of the anterior pair very robust; rami of the swimming-feet three-jointed (figs. 25, 26), fifth pair obsolete, represented only by three short plumose setae (fig. 27). Colour of the posterior part of the body faint reddish-brown, the anterior part nearly colourless (in spirit specimens). Length 0'85 mm. A t th e y e l l a n a t a l is , n. sp. (Plate VII. figs. 28-33.) Female. In general outline like Cavthocamptus (fig. 28). First thoracic segment coalescent with the head; posterior abdominal segments spinulose on the hinder margin ; furca very short; principal tail-setae equal to at least half the length of the body. Antennules slender, nine-jointed (fig. 29), shorter than the first cephalothoracic segment, and very sparingly setiferous ; antennae (fig. 30) bearing a minute one-jointed secondary branch. First pair of swimming-feet (fig. 31) short, both branches three-jointed, outer about equal in length to the first two joints of the inner branch ; second, third, and fourth pairs having the outer branch composed of three, the inner of one joint (fig. 32); fifth pair (fig. 33) foliaceous, two-jointed, basal joint wide and bearing four long setae on its inner and one on the outer lobe, terminal joint ovate and bearing three unequal apical setae. Length 0'75 mm. |
