AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 225 



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 Tritasta kergueleni ; but in at least one specimen the 

 anterior lobe of the second perseopod was only subacute, and was shorter than that in 

 the first perseopod. 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 setae, and curves 

 upwards. 



In these respects, therefore, these additional specimens tend to confirm the con- 

 clusion arrived at that all the forms of Polycheria 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 NOTOTROPIS A. Costa, 1853. 



Nototropis homochir (Haswell). 



Atylus homochir Haswell, 1885, p. 101, pi. xiii. figs. 5-7. 

 Nototropis homochir Stebbing, 1906, p. 333, figs. 77 and 78. 



1910A, p. 639. 



1910B, p. 455. 



South Africa, entrance to Saldanha Bay, Station 483 ; 25 fathoms. 21st May 



1904. Several specimens, largest 10 mm. long. 



These agree with STEBBING'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 perseopod (in the 

 female) is slightly produced into a small subacute lobe ; that of the fourth is not 

 produced, but in the fifth perseopod 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, e.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 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., 507.) 



