220 PROFESSOR CHARLES CHILTON ON THE 



South Orkneys, Scotia Bay, Station 325 ; 2-8 fathoms, gravel and clumps of 

 weed. Temperature 29-30. 6th December 1903. Several specimens, 

 the largest 14 mm. in length. 



These specimens are in most respects intermediate between P. pacifica and P. 

 fissicauda. They agree with the latter species, except that the last segments of the 

 peroeon are without dorsal teeth, or, in the largest, with a small tooth on the last 

 segment only. In this species, as in so many others, the dorsal teeth evidently vary, 

 for STEBBING notes the same thing in his description of P. pacifica. The Scotia specimens 

 have the lateral angle of the head rounded, as in P. fissicauda, and they resemble that 

 species also in the greater stoutness and the proportions of the joints of the antennae 

 and perseopoda ; the telson, however, is not split right to the base, but only very 

 deeply, as in P. pacifica. 



Through the kindness of Mr STEBBING I have been able to examine specimens of 

 P. pacifica from New Zealand sent to him years ago by Mr THOMSON. The comparison 

 of these with the Scotia specimens shows that it is not possible to maintain the two as 

 separate species. In the carination of the body, in the uropoda and telson, the New 

 Zealand specimens resemble those from the South Orkneys. They differ, however, in 

 having the appendages slightly more slender ; thus the upper antennae may have the 

 second joint of the peduncle considerably longer than the first, and in the peraeopoda 

 the propod may be nearly as long as the carpus, instead of being shorter, as described 

 by CHEVREUX. In them, too, the lateral angle of the head is produced into a small, 

 sharp, acute point. 



If we had to deal only with the New Zealand specimens and those from Wanclel 

 Island, it might be possible to look upon the latter as a separate but closely allied 

 species ; but, if that were done, a new species would have to be made for the South 

 Orkneys specimens, with characters almost precisely intermediate between those of the 

 other two, while future examination of specimens from some fresh locality would probably 

 necessitate the establishment of another intermediate species on very trivial points of 

 difference. I therefore think it much the best course to consider all the specimens as 

 belonging to one widely spread sub-Antarctic and Antarctic species which, through isola- 

 tion, has become slightly modified into two or three local varieties. 



Genus POLYCHERIA Haswell, 1879. 



Polycheria antarctica (Stebbiug). 



Dexamine antarctica Stabbing, 1875, p. 184, pi. XV.A, fig. 1. 

 Polycheria tenuipes Haswell, 1880B, p. 345, pi. xxii. fig. 8. 



Stebbing, 1906, p. 520. 

 brencornis Haswell, ISSOu, p. 346. 

 obtusa G. M. Thomson, 1882, p. 233, pi. xvii. fig. 3. 

 Tritxta kergueleni Stebbing, 1888, p. 941, pi. Ixxxiii. 



antarctica Walker, 1904, p. 266, pi. iv. fig. 25. 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., 502.) 



