156 



Distribution, British Isles (Brady), Heligoland (Glaus), Franz Jos 

 Land (Scott). 



98. Amphiascus imus (Brady). 



(PI. XCVII). 

 Stenhdia ima, Brady, Monograph of British Copepoda, vol. II, p. 35, PI. XLIII, figs. 1 1 



Specific Characters. Female. Body exceedingly slender and elongated, 

 sub-linear in form, with the anterior division scarcely broader than the posterior. 

 Cephalic segment about the length of the 3 succeeding segments combined; ros- 

 trum very long, lanceolate in form, with the tip acutely produced. Urosome a 

 little shorter than the anterior division, last segment about the length of the pre- 

 ceding one. Caudal rami very short, being almost twice as broad as they are 

 long, and obliquely truncated at the tip, inner corner more prominent than outer, 

 the 2 middle apical setae considerably thickened at the base, and distinctly spinu- 

 lose in their outer part. Anterior antennae very slender, 8-articulate, 2nd joint 

 the largest, 4th joint considerably longer and narrower than 3rd, terminal part 

 not nearly attaining half the length of the proximal one. Posterior antennae with 

 the outer ramus rather slender and elongated, middle joint well defined and seti- 

 ferous. 1st pair of legs comparatively slender, with the outer ramus about half 

 as long as the inner, middle joint scarcely longer than the 1st, terminal joint but 

 little smaller, and armed with 3 spines and 2 geniculate setse; inner ramus with 

 the 1st joint long and narrow, more than twice as long as the other 2 combined, 

 last joint considerably longer than the 2nd, and linear in form, finely spinulose 

 outside, and carrying on the tip a slender claw, a somewhat longer seta, and a 

 small hair-like bristle inside the latter. Natatory legs rather slender and of normal 

 structure. Last pair of legs with the distal joint comparatively narrow, oblong 

 in form, with only 5 marginal setse, the 2 apical ones slender, hair-like, the oth^r 

 3 rather small; inner expansion of proximal joint large, triangular, extending 

 considerably beyond the middle of the distal joint, marginal seta? 5 in number, 

 and all well developed. Ovisacs very narrow and only slightly divergent. 



Male of a narrow and slender form similar to that of the female, and having 

 the anterior antennae transformed in the usual manner. 2nd basal joint of 1st paii 

 of legs forming, inside, 3 strongly chitinised dentiform projections in addition tc 

 the usual spine. Inner ramus of 2nd pair of legs considerably shorter than the 

 outer, distal joint only slightly longer than the proximal one, and carrying out- 

 side near the tip 2 closely juxtaposed spiniform appendages of unequal size, the 

 proximal one being much the stronger. Last pair of legs rather unlike those ir 



