8 4 



CRUSTACEA MALACOSTRACA. III. 



Remarks. This group comprises three genera from our area, two among them established 

 as new (see the foot-note to Nannoniscelld). The animals are in general aspect somewhat similar to 

 species of latu'rn, but they differ from all Ianirini in several important features, above all in the man- 

 dibles. The antennulse are inserted on the upper surface of the head somewhat from the lateral margins 

 and considerably or far behind the anterior margin of the head; between the antennulse the surface 

 of the head shows a median broad area narrowing forwards, and both on the sides end in front con- 

 spicuously marked off, on the sides generally by keels or sharp margins, while its anterior end generally 

 is free, seen from above limited by a line; the shape of this part, which I name the front area, 

 affords excellent characters. 



Nannoniscella n. gen. 



Description. Body considerably flattened. Head anteriorly irregularly rounded, with the 

 front area well developed and reaching nearly beyond the anterior margin (PI. VIII, figs, i a — i b); the 

 head is laterally expanded, with each lateral part produced forwards as a somewhat large triangular 

 plate outside the proximal part of antennula and antenna. — Antennulse moderately short ( figs. 

 i a — i b); first joint large and thick; second joint slender and shorter than the first; flagellum with 

 few joints. Antennae intermediate in shape and length between those in lanira and Nannoniscus\ squama 

 well developed, triangular; fifth and sixth peduncular joints rather long. — Mouths-parts (PI. VII, figs. 

 7 a — 7 d) in the main as in Nannonisctis\ left mandible (fig. 7 a) has the incisive part somewhat long 

 and slender, the movable lacinia thin, the setse moderately numerous, the molar process directed some- 

 what backwards and very slenderly conical, with some short setse on the end. Maxillse (fig. 7 c) with 

 the inner lobe somewhat narrow. Maxillipeds (fig. 7 d) long; second joint moderately large, somewhat 

 less than twice as long as broad, its lobe long, not quite twice as long as broad ; third to fifth joints 

 very broad, and the fourth a little broader than long; sixth joint small with an oblong lobe, seventh 

 quite small; epipod very long and proportionately narrow, nearly four times as long as broad. 



Thoracic segments (fig. 1 a) rather crowded together and rather expanded; fifth and sixth seg- 

 ments with more than half of their posterior margins very concave, while seventh segment has the 

 major part of its anterior margin very convex, and the segment itself is more than twice as long at 

 the middle than at the sides; the dorsal limit between sixth and seventh segment is distinct in its 

 entire length, but whether the articulation is movable is somewhat dubious. In front of the lateral 

 part of first segment is seen a somewhat small narrow plate (fig. 1 b, ep) projecting outwards and for- 

 wards, and this plate must be considered an epimeral process from the base of first pair of legs. - 

 All legs of middle length, rather slender and adapted for walking (figs. 1 d — 1 e); but first pair are yet 

 somewhat shorter, and distally more robust than the other pairs; seventh joint with its short claw is 

 on first pair (fig. 1 d) of very moderate length, on the other pairs (fig. 1 e) somewhat longer and 

 slightly thinner; an accessory claw not developed. 



Abdomen broad, laterally much expanded (figs. 1 a and 1 f), posteriorly rounded. Operculum in 

 the female oblong, and it occupies a very small part of the ventral surface (fig. 1 f). — Uropods ventral, 

 moderately small, biramous, with the rami unjointed. — (Male unknown). 



