142 



head protrudes somewhat like a small triangle, besides, we see a knot-like protuberance, 

 somewhat in front of the middle, at a short distance from the outline of the back. The 

 head is exceedingly small in proportion to the trunk, and it is distinguished by the particular 

 solidity of the chitinised parts to the front and on the sides, which, moreover, laterally and 

 anteriorly extends considerably on the lower surface, so as to render the area with the 

 appendages somewhat smaller than in the other species. The frontal margin naked (fig. 5c). 

 Antennulae slender, of medium length, second joint proportionally longer than in the preceding 

 species, the setae of about medium length. Antennas 3-jointed, basal joint short, second 

 joint longer' than the third, and the latter longer than the seta. Mouth large, with border 

 of medium breadth. Additional branch of the maxillulse well developed. Maxillae rather 

 small, their basal joint smooth. Maxillipeds comparatively short and slender, yet somewhat 

 longer than in S. DulicMce; the basal joint has one or two stripes of excessively short hairs 

 (not shown in the drawing) on the inner side, and similar hairs on the inner part of the 

 terminal margin; second and third joints separated, the last joint pointed. Sub-median 

 skeleton provided with thick lists, naked; a double list between the head and the trunk, 

 somewhat behind the base of the maxillipeds. Lateral margin of the head naked. Trunk 

 naked; the trunk-legs are small but conspicuous, rounded knots without setae — thus deviating 

 much from all other species. Genital area (fig. 5d) somewhat narrower than the head, much 

 broader than long, firmly chitinised all over; it has a long, somewhat concave, anterior 

 margin, convex, oblique lateral margins and a shorter, deeply incised, posterior margin. 

 The genital apertures situated somewhat behind the middle of the plate ; they are of medium 

 size, close together anteriorly, and somewhat diverging posteriorly. The caudal stylets in 

 close proximity on the plate close to its posterior margin; they are small, each ending in a 

 rather long seta. The whole genital area naked. (In the illustration the orifices of the 

 receptacula seminis are seen at a short distance in front of the genital apertures). 



MALE, OVISACS, LARVA and POST-LARVAL DEVELOPMENT. Unknown. 



HABITAT. In the marsupium of a female of Acanthozone cuspidata (Lepech.) 

 from the Kara Sea was found a single female. 



25. Sphseronella frontalis n. sp. 



(PL VII, fig. 6a— 6i; pi. VIII, fig. la— le). 



FEMALE. The largest specimen (fig. la) is l'84mm. long and 171mm. broad, 

 and the thickness about three fifths of the breadth. The body is narrower towards the 

 front, and its long posterior outline is sligthly concave in the middle. The head nearly 

 middle-sized and distinctly defined from the trunk. An excellent character of this species 

 is that the naked frontal margin expands in the middle into an oval, transverse, flat cup 

 (fig. Id), the breadth of which somewhat exceeds the diameter of the basal joint of the 



