168 DISCOVERY REPORTS 



Gnathopod i, 6th joint slender and cylindrical, approaching in shape, though not in 

 length, the 6th joint of gnathopod 2. Peraeopods 3-5, 2nd joint with hind margin 

 obscurely serrulate. 



Colour (as preserved) orange-brown, formed by numerous close-set stellate 

 chromatophores ; eyes darker, reddish-brown. 



Remarks. It is probable that some of Chevreux' specimens from Petermann Island 

 belong to this species. He refers to an ovigerous $, 6 mm. in length, without any dorsal 

 teeth. He also mentions that some examples had a punctuated coloration, with brick- 

 red eyes. The respective localities are not very far distant from one another. 



Family PLEUSTIDAE 



Stebbing, 1906, pp. 309, 728. 



The only Pleustid hitherto recorded from the southern hemisphere is Mesopleustes 

 abyssorum (Stebb.) from Marion Island. 



Genus Austropleustes, Brnrd. 

 Barnard, 1931, p. 428. 



Rostrum short. Side-plates moderate. Antennae slender, elongate. Upper lip incised. 

 Outer lobes of lower lip widely separated. Mandible with molar feeble, conical, 

 setulose; 3rd joint of palp shorter than 2nd. Palp of maxilliped with 3rd joint apically 

 produced as in Stenopleustes (Fig. 103/). Gnathopods 1 and 2 subchelate, rather slender. 

 Dactyls of peraeopods 1-5 with a denticle at base of unguis. Uropod 3 with peduncle 

 apically produced on lower margin to support the rami, of which inner is much longer 

 than outer, and triquetral in cross-section. Telson more or less boat-shaped, apically 

 more or less notched. Genotype: A. cuspidatus n.sp. 



Remarks. The mouth-parts of the species described below are in agreement with 

 those of Stenopleustes, except the molar of the mandible, which is rather feeble but not 

 as feeble as in Pleustes and Neopleustes. This feature, in conjunction with the peduncle 

 of uropod 3, warrants generic separation. The structure of the peduncle of uropod 3 may 

 be compared with that of Oradarea described above, or that of Liouvillea. 



Austropleustes cuspidatus, Brnrd. (Fig. 102). 

 Barnard, 1931, p. 428. 

 Occurrence: St. 170. South Shetlands. 2 $$ (1 ovig.) 15 mm. 



Description. Integument (as preserved) moderately firm, with minute, transversely 

 elongate granules, chiefly on the hinder half of body. Rostrum extending to just half- 

 way along 1st joint of antenna 1. Eyes large, round-oval, yellowish. Head and peraeon 

 segments 1-5 feebly carinate. Peraeon segments 6 and 7 each with a pair of dorsal 

 cusps; segment 7 with a lateral tooth on posterior margin, nearer the side-plate than the 

 dorsal cusps. Side-plates, as in S. nodifer (Sars, 1895, pi. cxxv, fig. 2). Pleon segments 



