i62 DISCOVERY REPORTS 



are present all round this lobe and also on the outer margin of the lamella). The coxopodite bears a 



coxal lobe in the breeding female. 



The second thoracic appendage is shown in Text-fiig. 9^. It is considerably smaller and shorter than 

 the remaining appendages which increase in length from before backwards. The second, third, fourth 

 and fifth pairs are all subchelate, the last three pairs, which are directed backwards, are ambulatory 

 (Text-fig. 9c of sixth thoracic appendage). 



The pleopods are of the usual type, the form of the second pleopod of the male is shown by 

 Nordenstam (1933, p. 96, text-fig. 22c, d). Mention has already been made of the form of the uropod. 



Distribution. Nordenstam's specimens were collected off the coast of South Georgia; those of the 

 Discovery collections from South Georgia; SchoUaert Channel, Palmer Archipelago; and Admiralty 

 Bay, King George Island, South Shetlands. 



Edotia corrugata n.sp. (Plate VIII, figs. 1,2; Text-fig. loa-l) 



Occurrence. St. WS 809: 8. i. 32, 49° 29' S., 66° 27' W., 107-104 m., 2 S3 and 2 5$, one breeding and the other 

 non-breeding. 



The holotypes are from St. WS. 809. 



Description. The ^o^_y of the male (Plate VIII, fig. i) is longer and narrower than that of the female 

 (Plate VIII, fig. 2), which is compact and strongly arched; the male measures 6-5 mm. in length and 

 2-6 mm. in greatest breadth; the female 5-5 mm. in length and 275 mm. in greatest breadth, the 

 length: breadth ratio of the male is 2-5:1 as compared with a 2:1 ratio in the female. 



The head (Plate VIII, figs, i, 2) is almost rectangular, broader than long, with the posterior margin 

 slightly longer than the anterior; the antero-lateral angles are rounded and the anterior margin is 

 excavated for the reception of the antennules. The eyes, which are small and contain little pigment, 

 are situated on either side midway between the anterior and posterior margin of the head, some distance 

 in from the lateral border. The posterior part of the head is raised and separated from the anterior 

 part by a groove ; in the middle of the latter is a single large, rounded protuberance, which does not 

 show clearly in the photographs of the entire animal. 



The pereion somites in the male are subequal in length, except for the first which is only half the 

 length of the second. They are all supplied with well-developed pleura which, in the first four somites, 

 overhang the bases of the limbs. In the last three they are fused with the dorsal extensions of the 

 coxal plates of their respective limbs. The posterior half of each somite is raised in a pronounced 

 transverse ridge, which extends over the complete width of the somite and its pleura. The crests of 

 the ridges are rounded and give the animal a corrugated appearance when viewed from the side. 

 Each pleuron is broad, being a little over half the width of the tergum from which it is separated by a 

 slight groove; a further groove is present on the pleuron itself. In the hinder three somites these 

 grooves represent the line of fusion of the pleura with the coxal plates. 



The pleura, the outer margins of which are rounded, are curved slightly forwards on the first three 

 pereion somites, on the fourth they are straight and the posterior three are directed slightly back- 

 wards. In the female (Plate VIII, fig. 2) the first five pereion somites are considerably broader than those 

 of the male and are strongly arched, but the arrangement of the ridges and grooves is similar in both 

 sexes. The form of the coxal joint and its outgrowths has been considered in the introduction to the 

 genus (p. 155). 



The abdomen, which is somewhat elliptical in shape and slightly broader in the female than in the 

 male, is about a third of the length of the body ; its posterior tip is rounded. A small anterior segment 

 is indicated by a transverse groove. Behind this groove the whole of the dorsal surface is elevated, but 



