AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 481 
Genus Mrropetia G. O. Sars, 1892. 
Metopella ovata (Stebbing). 
M-topa ovata Stebbing, 1888, p. 764, pl. xlii. 
5 5 a 1906, p. 183. 
South Orkneys, Scotia Bay, Station 325a; dredge, 2-8 fathoms; temperature 
29°-30°. 6th December 1903. Several specimens, none exceeding 3 mm. 
in length. 
South Orkneys, Scotia Bay, Station 325; 9-10 fathoms. April 1903. Three 
small specimens. 
Several of these are females bearing eggs, and none can be said to be certainly 
males. ‘These specimens agree closely with the description given by SreBBiNe, and 
have the basal joints of the fourth and fifth perseopods narrowed as given in the 
diagnosis of the genus. The gnathopods, uropods, and telson are all in close 
agreement with the figures given in the Challenger Report; the accessory flagellum 
on the upper antenna is present, though extremely small, being about the same size as 
in Metopordes sarsw Pfetfer. ‘The palp of the mandible is short, and consists of a very 
short first joint, an expanded second joint bearing three sete along one margin, and a 
very short third joint tipped by a setum. 
Genus THAUMATELSON Walker, 1906. 
This genus was established by WatkerR in 1907 for his species 7. herdmani 
obtained by the Discovery Expedition. The Scotia obtained several specimens from 
the South Orkneys of what appear to be two additional species of the same genus. 
The genus is mainly characterised by the very peculiar telson, which was described by 
WaLKER as “large, entire, oval, and set in a vertical plane on its longer edge.” ‘The 
telson in the two species | have now to describe agrees well with this description. 
The shape of the telson is probably associated with the extremely large side plates 
which cover all the appendages when these are withdrawn, and enclose the animal so 
that it looks like a small bivalve shell; when this is done the pleon is folded in under 
the side plates which appear to overlap the telson all except a small thicker ridge along 
its dorsal margin, which fills the small slit between the right and left side plates. 
In the mouth parts the genus agrees well with the characters of the family Meto- 
pidz ; one species, however, is peculiar in having the second gnathopod chelate. 
Thaumatelson walkert, sp. nov. (Pl. |. figs. 11-15.) 
South Orkneys, Scotia Bay, Station 325. April and May 1903. Several 
specimens, the largest 3 mm. in length. 
Specific Description.—In general characters (see fig. 11) similar to 7. herdmanz, but 
with the side plates even larger, the fourth segment being longer than any of the others 
