CRUSTACEA MALACOSTRACA. III. 12 j 



Occurrence. Ohlin has mentioned a single specimen from East Greenland ; it had been taken 

 at Lat. 7i°33' N., Long. 2i°3o' \Y., 106 fath. 



Distribution. East Spitzbergen: King Charles Island, Lat. 78-50' X., Long. 2-j°t,<)' E, 11 fath.; 

 2 spec. (Ohlin |. 



82. Ilyarachna spinosissima n. sp. 

 (PI. XI, figs. 10 a— 10 e; PI. XII, figs. 1 a— 1 c). 



Male and Female (without marsupium). — Head nearly as broad as second thoracic segment; 

 in the male (fig. 10 a) above with several subcylindrical processes and minute tubercles, each terminat- 

 ing in an articulated spine; four of the largest processes are placed in a row towards the posterior margin, 

 and the third large pair a little from the antero-lateral margins; in the larger female the processes and 

 tubercles are somewhat more numerous. — First joint of the anteunulse (fig. 10 a and 10 b) somewhat 

 oblong, with a few strong spines on the outer margin; the outer distal part is produced somewhat 

 forwards and terminates in a thick spine. — The body formed by the four proximal antennal joints 

 taken together is considerably larger than in / hirficeps, and has a few tubercles of verr different 

 size. — The mandibles have the palp well developed ; the left mandible (fig. 10 c) possesses a some- 

 what small movable lacinia and some five short setae, while the moderately small molar process tapers 

 from near the base to the narrow, setiferous end. The maxillipeds ifig. 1 a) with second joint propor- 

 tionately longer and the epipod larger than in / hirficeps. 



In the male (fig. 10 a) each of the four anterior thoracic segments has a pair of somewhat high 

 processes a little from the front margin, one pair or two pairs of lateral processes, and the fourth seg- 

 ment, besides, a pair of processes near the submediau part of the hind margin: each of these processes 

 is truncate with a terminal spine; fifth and sixth segments each with a larger number of processes 

 and small tubercles on the surface and the lateral margins; the small seventh segment (fig. 10 a and 

 1 b) has two dorsal processes and a spine on each lateral angle. In the female, which is much larger 

 than the male specimen, the same processes and tubercles are found on the segments and, besides, a 

 good number of tubercles. — Fifth pair of legs (fig. 10 ei differ much from those in /. hirficeps; fifth 

 joint is very moderately expanded, about two and a half times as long as broad, and with natatory 

 setae only on the upper margin, while the opposite margin has some spines, three of which, on the 

 proximal third, long and strong; sixth joint is not expanded and without real natatory setae. 



Abdomen (fig. 1 b) oblong-triangular as in the preceding forms, but the proximal half of its 

 lateral margins has some protuberances, all probably terminating in spines; the upper surface has 

 several moderately small or quite small tubercles almost regularly arranged on its median area and 

 towards the lateral margins. — Operculum in the female without any conspicuous keel. — Uropods 

 (fig. 1 c) with the endopod somewhat long and no exopod. 



Length of the female without marsupium 6 mm., of the male 3-8 mm. 



Remarks. I. spinosissima is instantly separated from all other species of the genus by the 

 numerous processes and tubercles on the surface of the body. The mandibular palps and the absence 

 of the exopod on the uropods shows it to belong to this genus. 



