28 CRUSTACEA MALACOSTRACA. III. 



pleopod of the median lamella has the posterior margin concave and somewhat oblique, as the distal 

 outer corner is produced into a triangular process directed backwards. The female operculum (fig. i h) 

 is slightly longer than broad. - - The terminal joint of the uropods a little less than half as long as 

 the abdomen, with some stiff setae along both margins. 



Length of a male 2mm.; the largest female is without marsupium and nearly 1-8 mm. long. 



Occurrence. Taken by the "Ingolf" at a single station. 



South- West of Iceland: Stat. 78: Long. 6o37' N., Lat. 27^' W., 799 fath., temp. 4-5; 9 spec. 



Group II. Haploniscini. 



In general appearance somewhat similar to animals among the terrestrial Isopoda, excepting, of 

 course, in having the abdomen not divided into segments. Head free. Eyes wanting. Antennae without 

 normal squama, frequently with a long process on third joint. Mandibles normal; molar process sub- 

 cylindrical or thickened towards the end, but otherwise as in lanira. Maxillary palp with second joint 

 not expanded, slender; the two distal joints well developed. The three, or at least two, posterior thor- 

 acic segments coalesced at least on the dorsal side and immovably coalesced with the abdomen. All 

 thoracic limbs are slender walking legs, with seventh joint at least moderately long, and on the posterior 

 pairs rather long, the claw slender and no accessory claw. Uropoda minute and uniramous, or wanting. 



Remarks. The group comprises two genera, one of them new. The animals are very small, 

 smooth, and live in considerable or great depths. 



HaploniSCUS Richardson. 



Description. Body more or less depressed. Front margin of the head distinctly sinuate or 

 with a short process. -- Antennulse (PI. II, figs. 2 a and 4b) moderately short; first joint thick, twice 

 to four times as thick as, but a little shorter than, the second ; flagellum with a low number of joints. 

 Antennae of very moderate length or rather short; first joint scarcely discernible; third joint with an 

 acute, strong or long process, but whether this process may be a peculiarly developed squama is 

 questionable; fifth joint considerably thicker than the sixth; flagellum shorter than the peduncle. - 

 Mandibles (figured by Sars) nearly as in lanira, Maxillipeds (fig. 2 e) with the two proximal joints 

 moderately broad, the lobe from second joint broader than this joint and with few coupling hooks; 

 the joints of the palp slender; epipod large, nearly triangular. 



Thoracic segments conspicuously expanded laterally, but their lateral margins are straight or 

 slightly convex in their full length; epimeral processes wanting. The three posterior segments either 

 well marked off from each other and from abdomen towards their lateral margins, while their broad 

 dorsal median parts are coalesced or even fused, or -- in H. armadilloides -- the articulation between 

 fifth and sixth segments seems to be not fully undeveloped, while the two posterior segments and 

 abdomen seem to be immovably coalesced, though moderately distinct sutures between them remain 



