26 CRUSTACEA MALACOSTRACA. II. 



third segment combined, rather slender. First joint, seen from the side, not fully five times as long 

 as deep, decreasing conspicuously in depth from the base towards the middle and somewhat longer 

 than the two other joints combined; third joint only a little longer than the second. — Antennae 

 (fig. 4c) moderately slender; second and third joints without any .spine at the distal upper angle; 

 fourth joint (in reality formed by a fusion of fourth and fifth joints) two and a half times as long as 

 the penultimate joint. 



Chelipeds (fig. 4 d) somewhat slender. Carpus conspicuously longer than the basal joint, two 

 and a half times as long as deep. Chela much longer than the carpus, nearly two and a half times 

 as long as broad, with the posterior margin feebly concave; the fixed finger only slightly broader than 

 the proximal part of the movable and keeping the same breadth from near the base to the middle; 

 the movable finger is conspicuously longer than the front margin of the hand, moderately slender, 

 with the major part of its incisive margin almost convex, at the base far from touching the fixed 

 finger, so that the fingers, when their distal parts are crossed, are very forcipate, leaving a consider- 

 able triangular interval between their proximal lialves. 



Fifth thoracic segment (fig. 4 b) as long as the sum of the three preceding segments and 

 scarcely or slightly longer than the sixth segment. — The thoracic legs are slender and somewhat long. 

 Second pair (fig. 4 e) with sixth joint a little shorter than fourth and fifth joints combined (the arti- 

 culation between these two joints forgotten on the figure) and almost half as long again as seventh 

 joint with claw, and seventh joint itself is much shorter than the claw. Third pair (fig. 4 f) with the 

 sixth joint not quite half as long again as the fifth and twice as long as seventh joint with claw; 

 seventh joint and claw equal in length; spur on fifth joint moderately slender, not expanded; con- 

 siderably less than half as long as sixth joint. Three posterior pairs of legs (fig. 4 g) with second 

 joint long and slender, sixth joint a little longer than the fifth, seventh joint rather short, claw ex- 

 tremely short; the spur slender and only about as long as the diameter of the joint. 



The abdomen somewhat longer than the sum of the two preceding segments (fig. 4 a). 

 Pleopods well developed; their rami with very long .sette (fig. 4h). — Uropods .somewhat long (fig. 41); 

 endopod with the proximal joint a little longer than the distal; exopod slender, reaching a little or 

 somewhat beyond the end of the first joint of the endopod, and its two very distinct joints subequal 

 in length. 



Length of a female with the marsupium half developed i.iy™™. 



Remarks. This small species agrees with P. forcipatns in having no eyes and the chelfe 

 strongly forcipate, but it differs from it in several features, especially in possessing well developed 

 pleopods with long setae, longer uropod.s, longer and more slender chelipeds and legs. P. abyssi bears 

 some resemblance to P. octilatus n. sp., but the latter differs in having distinct ocelli, the chelae con- 

 spicuously less forcipate, the exopod of the uropods longer and in several jjarticulars in the legs. 

 From the other northern species of the genus P. abyssi differs greatly, above all in having the chela; 

 strongly forcipate. 



Occurrence. The "Ingolf" secured this species at a single station. 



Davis Strait: St. 36: Lat. 61° 50' N.. Long. 56° 21' W., 1435 fm., temp. 1.5°; 3 spec. (2 are females 



with the marsupium half developed). 



