3SO DISCOVERY REPORTS 



but both exopod and endopod are developed. In the male the coxal plates of the seventh 

 thoracic somite extend posteriorly to a short distance behind the attachment of the 

 uropod ; in the female they are not as long: in both sexes they extend beyond the pleural 

 plates of the second abdominal segment, but in the female they only reach as far as the 

 extremities of the third. 



Remarks. The specimens were collected to the south of the South Shetland Islands 

 at depths of from 93 to 335 m. ; the largest adult male measures 41 mm. in length and 

 3 1 mm. in breadth and is considerably larger than any of Richardson's specimens. The 

 largest specimen, which was collected at a depth of 20-40 m., measures 35 mm. in 

 length and 25 mm. in breadth. 



The appendages, with the exception of the antennule and the antenna, are not 

 described in the original paper: a few additional observations are therefore included 

 here. 



The antennule (Fig. 20 a) consists of a peduncle of four and a flagellum of thirty-six 

 joints. The first joint of the peduncle is geniculate, and bears on its dorsal surface a well- 

 marked ridge, which has its anterior distal angle produced into a strong spiniform pro- 

 cess. The second joint is two-thirds the length of the first and has a similar dorsal ridge, 

 which, however, is produced to form two more processes, one midway along its posterior 

 margin, and the other, on its anterior margin, slightly nearer the distal extremity. The 

 third joint is about equal in length to the first, but is slightly curved and only half its 

 width ; the fourth is a quarter the length of the third and is broader at its distal than at 

 its proximal end. Long delicate hairs are present on the anterior margins of the first 

 two, and on the posterior of the second peduncle joints. The first joint of the flagellum 

 is about half the length of the last peduncular joint; the second and succeeding joints are 

 half the length of the first, the length increasing towards the distal end of the flagellum ; 

 the terminal joint is equal in length to the penultimate, but is only half its breadth. 

 A sensory hair is present at the distal end of each of the last twenty joints. 



The antenna is made up of the usual five peduncular joints and a flagellum of nine- 

 teen. The first joint of the peduncle is short ; the second is three times the length of the 

 first with short hairs on its anterior margin, whilst the third is the same length as the 

 first. A rounded tubercle is present on the dorsal surface at the distal end of both second 

 and third joints and is larger on the former than the latter. The fourth and fifth joints 

 are each twice as long as the second, but the fourth is considerably broader than the 

 fifth ; the flagellum is one and a half times as long as the fifth joint of the peduncle. 



The mouth-parts are of the usual type ; the form of the cutting edges of the mandibles 

 may be seen from Fig. 20 b. The outer lobe of the maxillula bears ten stout spines and 

 an inner, more delicate, pectinate one on its truncate distal extremity. There are two 

 pectinate setae on the outer, three on the inner and about fifteen on the fixed lobe of the 

 maxilla. 



The basipodite of the maxilliped is separated by a suture from the lamella. The second 

 joint of the palp is broad ; the inner and outer margins of the third joint are almost 

 parallel, but at about one-quarter of the distance from the distal end, the outer margin 



