AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 507 
eye showed intermediate sizes, though in none of those examined was it quite so small 
as in the small South Orkneys specimens first examined. ‘The side plates seem to be 
acutely produced as described for Tritzta kergqueleni ; but in at least one specimen the 
anterior lobe of the second perzeopod was only subacute, and was shorter than that in 
the first perzeopod. In the third uropods the outer branch is about half as long as the 
inner ; in both branches the extremity is narrowed, almost free from sete, and curves 
upwards. 
In these respects, therefore, these additional specimens tend to confirm the con- 
clusion arrived at that all the forms of Polychera are referable to one species. They 
present a peculiarity, however, in having the telson particularly long, reaching to the 
end of the third uropod ; in side view it appears thick, scarcely narrowing distally, and 
the margin is fringed with stout spinules. In the smaller South Orkneys specimens it 
is much shorter, reaching hardly half way along the branches of the uropod, and the 
spinules on it are few and much less prominent. In the specimen figured in the 
Challenger Report the telson is intermediate, reaching more than half way to the end 
of the third uropod, and bearing numerous spinules. In the smallest of the additional 
specimens now being described it is hardly so long as in the largest, but still longer 
than in some Discovery specimens from M‘Murdo Sound that are themselves larger 
in size. It seems probable that the especially long and strong telson is a character 
developed beyond the average, like the large eye, and that it attains its full size only 
in specimens of a definite age—possibly it lengthens rapidly at a particular moult. | 
Genus Norotroptis A. Costa, 1853. 
Nototropis homochir (Haswell). 
Atylus homochir Haswell, 1885, p. 101, pl. xiii. figs. 5-7. 
Nototropis homochir Stebbing, 1906, p. 333, figs. 77 and 78. 
1910a, p. 639. 
1910s, p. 455. 
” ” ” 
” 3° ” 
South Africa, entrance to Saldanha Bay, Station 483; 25 fathoms. 21st May 
1904. Several specimens, largest 10 mm. long. 
These agree with Stepsine’s description, except in a few small points: e.g. the third 
joint of the palp of the mandible is not longer than the second, but barely equal to it 
in length; the lower hind corner of the basal joint of the third perzeopod (in the 
female) is slightly produced into a small subacute lobe; that of the fourth is not 
produced, but in the fifth pereeopod it is produced as a subacute lobe reaching about 
to the end of the ischium. 
The points which distinguish this species from some of those found in northern 
seas, ¢.g. from N. vedlomensis (Bate and Westwood), do not seem to be very great; 
it appears to differ from that species, however, in the amount of production of the 
basal joints of the perseopoda three to five, and in the size and arrangement of the ~ 
