CRUSTACEA MALACOSTRACA. III. 



59 



HaplomeSUS Richardson. 



Body slender or extremely slender. Antennulse well developed, 6-jointed. Antennae with third 

 joint elongate, two and a half times or more as long as the fourth joint. Maxillipeds (fig. i f) with 

 second joint extremely large, the lobe more than half as broad as the joint and much shorter than 

 broad; the palp not two-thirds as long as second joint itself — the lobe not included — and its second 

 and third joints of very moderate size and narrower than the lobe of second joint, though they are 

 much expanded, each conspicuously broader than long. — The three posterior thoracic segments and 

 abdomen immovably coalesced, constituting an extremely long, stiff part. First pair of thoracic legs 

 with fifth joint a little less deep than the fourth, not expanded and of normal shape. — Uropods one- 

 jointed, short. 



Remarks. This pretty genus has been established on /. quadrispinosus G. O. Sars. The ma- 

 terial contains this form and besides 4 new species, all deep-sea forms. Their exoskeleton is extremely 

 brittle, and numerous specimens are therefore very mutilated. The colour of the animals generally 

 whitish or pure white, but several of the specimens, especially females, of //. quadrispinosus are greyish. 



36. Haplomesus quadrispinosus G. O. Sars. 

 (PI. V, figs. 1 a— 1 p). 



1879. Ischnosoma quadrispiuosum G. O. Sars, Arch. f. Math, og Naturv. Vol. IV, p. 435. 

 ! 1885. G. O. Sars, North-Atl. Exp. I, p. 126; PI. 11, figs. 26—29. 



Male. Body (fig. 1 a) extremely slender, from about eight to nearly eight and a half times as 

 long as broad across the first thoracic segment — the processes not included in the breadth. The 

 integument of the whole body, excepting the thoracic processes, closely set with very fine, sharp 

 granules, and at the lateral margins of the posterior part of the thorax and of the abdomen these 

 granules are a little larger (fig. 1 h), triangular. 



Antennulae, when directed backwards, reach beyond the middle of fourth thoracic segment; 

 second joint (fig. 1 b) is extremely long, conspicuously more than half as long again as the four distal 

 joints combined; third joint nearly as long as the flagellum. — Antennae very long and slender, a 

 little shorter than the thorax; third peduncular joint long, but yet considerably shorter than second 

 antennular joint; fifth peduncular joint subcylindrical; sixth joint very slender, but yet distinctly in- 

 creasing in thickness from base to end, and a little longer than or about as long as the fifth; flagellum 

 very thin, somewhat or considerably longer than sixth peduncular joint, with about 18 — 20 joints. 



Thorax on first segment with a pair of lateral processes, which are very long, from a little to 

 considerably longer than the breadth of the segment, moderately slender, tapering, acute, directed out- 

 wards, much forwards and (fig. id) very considerably upwards; third segment has a pair of lateral 

 processes half or less than half as long as the first pair and frequently directed more outwards, but 

 otherwise rather similar. (In the later "remarks" some variation in the processes is mentioned). Fourth 

 segment a little longer than second and third segments combined. Fifth segment is extremely elongate, 

 even slightly more than half of the entire animal, in adult specimens nine to nearly ten times as long 

 as broad somewhat before its middle, subcylindrical to the beginning of the short leg-bearing part, 



