64 DISCOVERY REPORTS 



proximal part of anterior margin with a few spinules, the distal part and the whole 

 posterior margin with short plumose setae, 3rd, 4th and 5th joints also with plumose 

 setae as well as a few longer simple setae, dactyl slender, two-thirds length of 6th joint. 

 In the juvenile the 2nd joint is more oblong than square and the hind margin is produced 

 in a strong straight spine. Peraeopods 4 and 5, 2nd joints not abnormally thick, ovate, 

 hind margin strongly serrate and with short plumose setae, armature of other joints as in 

 peraeopod 3 ; peraeopod 4 slightly longer than 5. 



Uropods 1 and 2, rami subequal, acuminate, sparsely spinose. Uropod 3 extending 

 as far back as uropod 1 and slightly beyond apex of telson, rami lanceolate, 2nd joint 

 of outer ramus well developed, inner margin of both rami with long plumose setae. 



A single accessory branchia on both segments 5 and 6. 



Remarks. The extraordinarily shaped 2nd joint of peraeopod 3 fits within the 

 hollowed portion of the 5th side-plate when the limb is folded back. The whole animal 

 was covered with very fine particles of foreign matter due to the muddy nature of the 

 bottom ; and the setulose margins of the side-plates would seem to be for the purpose 

 of excluding such foreign matter from penetrating between them. 



Genus Allogaussia, Schell. 

 Schellenberg, 1926, p. 245. 



The first species here described is very like the species of this genus described by 

 Schellenberg, but shows the following peculiarities. 



Antenna 1 in both sexes very stout, 2nd joint of peduncle very short compared with 

 its breadth, 3rd easily visible dorsally, but ventrally entirely masked on inner side by 

 the 1st joint of flagellum, which is in continuity with the 2nd peduncular joint. First 

 flagellar joint stout and elongate, 1st joint of accessory flagellum also elongate. Epistome 

 expanding from quite near the bases of 1st antennae into a broad lamina, with a deep 

 narrow notch separating it from the upper lip (the latter feature as in Allogaussia). Side- 

 plate 4 fitting into a groove on side-plate 5, thus preventing the 2nd joint of peraeopod 3 

 from external movement over the posterior lobe of the latter. Uropod 3 extending 

 slightly beyond apices of uropods 1 and 2, well developed, rami with marginal setae. 

 Telson elongate, concave above. Accessory branchiae present on segments 5 and 6. 



Accessory branchiae are said to be absent in Allogaussia paradoxa, Schell. The man- 

 dibular palp is inserted " far behind " (no figure given), and the palp of maxilla 1 in the 

 new species has many more apical spinules than any of the three species described by 

 Schellenberg. 



The locking of side-plates 4 and 5 and the confinement of peraeopods 3 and 4 to 

 movement within the side-plates (as in Waldeckia and Kerguelenia) seems to be a greater 

 specialization than is found in the original three species of this genus, where, according 

 to Schellenberg's figures (1926, figs. 5 and 7), peraeopod 3 is freely movable outside 

 and over the posterior lobe of the 5th side-plate. The epistome, telson and uropod 3 are 

 not so very different, but the 1st antenna is entirely different and in conjunction with 

 the character of the side-plates almost makes a separate genus advisable. 



