CRfSTACRA MALAC08TRACA. Ill 



Haplomesus insignis n. sp. 

 (PI. V, figs. 3 - 3 d). 



Male. Very slender, about seven times as long as the breadth of the anterior segments. Body 

 very finely granulated, about as in //. anf tutus. 



Antennulte somewhat long (fig. 3 b). when stretched backwards reaching beyond the posterior 

 margin of third thoracic segment; second joint a little shorter than the head and first segment com- 

 bined, and a little longer than the sum of the four distal joints; third joint conspicuously thicker and 

 slightly longer than the flagellum. Antennae (fig. 33) somewhat more than half as long as the body; 

 third peduncular joint conspicuously shorter than in the two preceding species, somewhat shorter than 

 second joint of the antennulse; fifth joint increases conspicuously in thickness from the base to some- 

 what from the end; sixth joint is somewhat longer than the fifth and increases somewhat in thickness 

 from the base to the middle; flagellum about as long as sixth peduncular joint, i8-jointed, increasing 

 distinctly in thickness from the base to the middle, and tapering then to the thin end. 



The thorax has two pairs of very large, lanceolate processes (fig. 3 a) projecting respectively 

 from first and fourth segment, while the sides of second segment (fig. 3 b) are produced in very short 

 processes with the end obtuse. The processes of first segment are directed outwards, much forwards, 

 and rather feebly upwards (fig. 3 b), and their tips reach a little in advance of the front end of the 

 head; they are proportionately broad, four times as long as broad, lanceolate, subacute and somewhat 

 depressed. The processes of fourth segment are slightly shorter than in the first pair, besides they 

 are directed considerably less forwards, and only a little upwards. Fifth segment very elongate, but 

 yet considerably less than half as long as the entire animal, nine times as long as its breadth some- 

 what before the middle; the terminal widened part is somewhat narrower than the anterior segments. 



First pair of legs (fig. 3 c) agreeing as to armature with spines with those in H. angits/tts, but 

 the three distal joints are distinctly more slender than in that species. The other six pairs mutilated 

 or lost, but as far as can be seen they are more robust than in the two preceding species, but agree 

 with them in the fact, that second joints of fourth and fifth pairs, when directed respectively back- 

 wards and forwards, do not quite reach one another. 



Abdomen (fig. 3 a and 3 d) subtriangular in aspect, and on the whole somewhat similar to that 

 in H. angustus, especially as it has similar postero-lateral processes, but it differs in having the median 

 part of the posterior margin subangular, thus not broadly rounded, and the uropods arc somewhat 

 longer than in that species, somewhat more than twice as long as broad. The median lamella of 

 the operculum distally less narrow than in //. attfusttts. 



Length of the specimen 4-5 mm. 



Remarks. //. insignis is easily separated from the two preceding species by the large pro- 

 cesses on fourth thoracic segment In this character it agrees to some degree with H. tfnuisjrinis, but 

 in the latter species this second pair of processes are bent strongly forwards, and the abdomen is 

 totally different 



Occurrence. Taken by the "IngolP at a single deep station in the warm area. 



Davis Strait: Stat 36: Lat 6i5or N, Long. 562i' W., 1435 fath -' tetn P- r 5*5 * 



