OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 285 



men. Bate speaks of the first joint of the first antennae as furnished with a short, 

 obtusely pointed stylocerite. Hansen's fig. lb shows it, as I do, with a very small 

 acute tooth near the middle of the outer margin. The mandibles are not in agree- 

 ment with Bate's figure, except in regard to the penultimate joint of the palp, which 

 is of substantial proportions, not slender, as the mandibular palp is generally said to 

 be in species of Sergestes. The first and second maxillae are not notably different 

 from those in the last-named genus. In describing the first maxillipeds, Bate speaks 

 of the third or outer branch as free from hairs, which is at any rate not always the 

 case, though they might easily be missing by accident. The substantial character 

 and strongly spinose armature of the second maxillipeds may be judged from the 

 figure. The third, fourth, and fifth joints are subequal in length, while the sixth is 

 rather longer than any one of them. The seventh joint is short, blunt, narrow at the 

 base, widening towards the middle. 



In the first peraeopods the third and fifth joints are nearly equal in length, and 

 similarly the much more elongate fourth and sixth, both which are strongly spined, 

 the sixth faintly showing division into about fifteen jointlets. The fifth joint has on 

 its inner margin four spines of very conspicuous length, and distally a group of short 

 curved spines to antagonise with a similar group at the base of the sixth joint, as 

 in the genus Sergestes. The fourth perseopod is long and slender, the fifth slender 

 and short. 



The Challenger specimens were all females or not fully adult. It is therefore of 

 interest now to have one with the petasma of the male uninjured. Its complicated 

 structure will be best understood from the figure, although that omits one of the 

 median plates which are in contact at the base, and only hints at an additional 

 pair lying beneath the slender terminal pair and for the most part concealed by it. 

 The numerous hooks with which the various projecting lobes are studded probably 

 resemble those which Professor S. I. Smith has figured for his Sergestes robustus, 

 enlarging them one hundred diameters (U.S. Rep. Comm. Fish, 1884, pi. viii. 

 fig. 6a, 66). The second pleopod of a specimen which I take to be a female has, in 

 attachment to the short inner branch, a narrowly laminar appendage of considerable 

 length, distally furnished with setae on the surface and apically with several 

 unequal spines. The inner branch of the uropods is considerably longer than the 

 telson, but shorter than the outer branch. In every case, as with the scale of the 

 second antennae, this outer branch is apically damaged, the existing portion having 

 the outer margin smooth and unarmed. The telson in the basal half is more or less 

 parallel-sided, the distal half strongly tapering and ending abruptly in a sharp point, 

 the distal part setose at the sides. 



Length of specimen figured 42'5 mm., of which the carapace occupied 11 '5 mm. 

 In lateral view the hind margin of the carapace forms a double curve. Among the 

 pleon segments the shortness of the fifth and length of the sixth are conspicuous. 



Locality. — Lat. 48° 00' S., long. 9° 50' W. ; depth 1332 fathoms; Station 450. 



TRANS. ROY. SOC. EDIN., VOL. L. PART II. (NO. 9). 40 



