50 



front, and gradually tapering behind. Cephalic segment rather large and deep, 

 with the rostrum very prominent. Epimeral plates of the 3 succeeding seg- 

 ments rounded at the lateral corners. Last pedigerous segment comparatively 

 small. Urosome not attaining half the length of the anterior division, posterior 

 edges of the segment finely spinulose. Caudal rami about as long as they are 

 broad, and somewhat divergent, apical setae rather slender, the innermost but one 

 about twice the length of the urosome. Anterior antennae comparatively slender 

 8-articulate, terminal part not attaining l / 3 of the length of the antenna. Posterior 

 antennae very greatly developed, outer ramus, however, small, with 6 setae. Pos- 

 terior maxillipeds exceedingly large and powerful, hand nearly globose in form, 

 with the palm somewhat hollowed, its upper angle coarsely denticulate, dactylus 

 very strong and curved. First pair of legs rather strongly built, joints of the 

 outer ramus of about equal length, the distal one armed at the tip with 3 finely 

 denticulated claws; inner ramus 3-articulate, the outer 2 joints very small and 

 imperfectly defined, apical claw of same appearance as those of the outer ramus. 

 Natatory legs with the outer ramus much stronger than the inner, 1st joint the 

 largest, terminal joint rather narrow, with 4 coarse spines outside gradually in- 

 creasing in length distally. Last pair of legs with the inner expansion of the 

 proximal joint moderately broad, and provided with only 3 marginal spines. 

 Ovisac generally not very large, oval in form. 



Male somewhat larger than female, with the urosome narrower. Anterior 

 antennae very powerful, hand strongly dilated, dactylus simple. Outer ramus of 

 3rd pair of legs exceedingly large and robust, with the 1st joint fully as long as 

 the other 2 combined, last joint spatulate, armed with 3 very thick spines. Last 

 pair of legs much smaller than in female, distal joint oblong quadrangular in 

 form, proximal one not at all expanded inside. 



Colour light yellow. 



Length of adult female 0.90 mm., of male about 1 mm. 



Remarks. The above-described form is unquestionably that originally 

 recorded by 0. Fr. Miiller as Cyclops chelifer. In some cases, however, quite 

 different forms have been identified with Miiller's species. Prof. Brady has ap- 

 parently confounded this species with H. gracilis of Glaus, and some of the figures 

 given in his Monograph seem indeed to be more properly referable to that form. 

 On a closer examination, the present species may be easily recognized by the 

 pronouncedly compressed form of the body, and by the unusually large posterior 

 maxillipeds. Moreover, both in the structure of the antennas and of the legs, 

 well-marked differences from the other species are found to exist. 



Occurrence. This is one of the commonest of our Harpacticoids, being 



