CRUSTACEA MALACOSTRACA. II. 



31 



the base; tlie movable finger nearly as long as the front margin of the hand, conspicuously more 

 slender than the fixed finger; when the distal parts of the fingers are crossed there is a narrow or 

 no interval between their proximal halves. 



Fifth thoracic segment about three-fourths as long as the three preceding segments combined 

 and scarcely longer than the sixth segment. — Thoracic legs moderately long and rather slender, but 

 the posterior pairs vary a little in this respect. Second pair (fig. 2 f) with sixth joint almost as long 

 as fifth and fourth joints combined and a little shorter than seventh joint with claw. Third pair 

 (fig. 2g) with the sixth joint only a little longer than the fifth and not fully twice as long as seventh 

 joint with claw; the spur on fifth joint about, or more than, half as long as sixth joint, strongly nar- 

 rowed a little beyond the very broad base (fig. 2i) and with the distal half conspicuously expanded, 

 forming a very oblong plate with the end subacute or narrowly rounded. Seventh pair (fig. 2 h) with 

 fifth joint somewhat longer than the sixth, which is not fully twice as long as seventh joint with 

 claw; the spur not half as long as sixth joint, moderately narrow or somewhat thin, not expanded at 

 the middle. 



Abdomen almost as long at the two preceding thoracic segments combined. — Pleopods well 

 developed; the longest setae about three times as long as their rami and on the posterior pairs even 

 reaching the end of the uropods. — Uropods (fig. 2 c) somewhat long and slender; the endopod with 

 the proximal joint slightly longer than the distal; the exopod reaches about the middle of the distal 

 joint of the endopod, and its pro.ximal joint is always considerably shorter than the distal. 



Length of the largest female with marsupium (from the Kara Sea) 2.2"'", of large specimens 

 without marsupium 2.1 '""'. 



Subadult Male. The most characteristic difference between subadult males and the other 

 sex are the antennulae (fig. 2I), which have the first joint much thicker, the second somewhat to much 

 thicker, than in the other sex; the third joint is slender with a thickening below at the base. Fifth 

 and sixth thoracic segments somewhat shorter as compared with the three anterior segments than in 

 the females. The chelse (fig. 2 m) and the thoracic legs (fig. 20J vary conspicuously as to thickness. 

 Pleopods and uropods as in the females. 



Variety. At Stat. 25 the "Ingolf captured a number of specimens, all innnature and of both 

 sexes, which in some particulars differ from the other material. The largest female is only 1.4""", the 

 largest subadult male 1.3""". In the females the antennulae (fig. 2 k) are distinctly less slender than 

 usual, with first joint about four times as long as deep; the antennae are conspicuously thicker (fig. 2k) 

 with the fourth joint only twice as long as the penultimate, while second and third joints have a 

 slender spine instead of a stronger process on their upper distal angle. The cheke about three times 

 as long as broad; the thoracic legs on the whole a little more robust and the spur on third pair 

 scarcely as long as and somewhat more spiniform than in the t\pical form. The uropods normal. — 

 In the subadult male the antennulae (fig. 2n) have first and second joints nuich thickened, but the 

 third joint is more than half as long again as the second, the thickening is not confined to the short 

 proximal part but reaches to near the middle of the joint, and the proximal half of the joint is dis- 

 tinctlv conical, the distal half cylindrical. The antennae nearly as in tlie female, with the fourth joint 

 slis'htlv thicker. 



