96 DISCOVERY REPORTS 



It will be seen that the " tessellata " group, so characteristic of the Patagonian Region, 

 is altogether wanting in the Antarctic Zone. Another interesting fact clearly shown by 

 this table as well as by the map (Plate I) is that, although the genus Notothenia is 

 well represented by six species on the coasts of Graham Land and at the neighbouring 

 South Shetlands, it is represented in the Victoria Quadrant of the Antarctic Continent 

 only by A^. coriiceps, and has not been found at all in the Enderby and Ross Quadrants. 

 It may be noted that A^. coriiceps is probably not so demersal or littoral in its habits as 

 many other species of the genus, and the silvery young may be mainly pelagic. From 

 Graham Land species of Notothenia spread eastwards to the South Orkneys, South 

 Sandwich Islands, South Georgia and Bouvet Island in the Glacial District, and other 

 species occur in the Kerguelen-Macquarie District. In contrast to Notothenia, the 

 genus Trematomus occurs in all four quadrants of the Antarctic Continent, extending 

 northwards in the Weddell Quadrant to the South Orkneys and South Georgia, but not 

 reaching Bouvet Island ; it is absent altogether in the Kerguelen-Macquarie District. 



With regard to the Zoarcidae, the group next in importance to the Nototheniiformes, 

 I have little to add to the remarks on their distribution made by Regan {t.c, pp. 31-33). 

 Two of the Antarctic species are the southern representatives of the northern deep- 

 water genera Lycenchelys and Melanostigma : Melanostigma gelatinosum is found in both 

 Antarctic and Subantarctic Zones. The remainder are all generically distinct from the 

 northern members of the family. The two genera Lycodichthys and Austrolycichthys 

 (the first monotypic, the second with three species) are peculiar to the Antarctic and 

 are confined to the Glacial District. 



THE ANTARCTIC ZONEi 



This includes the coasts of the Antarctic Continent and all the islands lying on or to 

 the south of the Antarctic Convergence (fig. 59). 



To quote Regan {t.c, p. 33), "it is characterised by the complete absence of South 

 Temperate types, by the absence of Bovichthyidae [the most generalised family of 

 Nototheniiformes] and by the great development of other Nototheniiformes". The 

 percentage of genera peculiar to this region is high (about 67 per cent), and the per- 

 centage of peculiar Nototheniiform genera very high (85 per cent). The percentage of 

 species ranging beyond the limits of the Antarctic Zone is very low indeed (less than 



10 per cent). 



Glacial District 



This includes the coasts of the Antarctic Continent and neighbouring islands, 

 together with South Georgia, the South Sandwich Islands, and Bouvet Island, all 

 found within the extreme Umit of pack-ice. 



NoTOTHENiiDAE. Notothenia (7 species); Trematomus (13 species); Dissostichiis 

 (i species); Pleuragramma (i species). 



1 The data which follow are arranged exactly as in Regan's report (19146, p. 33) to facilitate ready re- 

 ference and comparison. 



