PATAGONIAN REGION I47 



Sardina, there is good evidence that the limits of these zones have fluctuated con- 

 siderably in comparatively recent times. He points out that fishes which descend to 

 considerable depths are less likely than shallow-water species to find the Tropical Zone 

 an impassable barrier, and, in this connection, it may be noted that almost all the fishes 

 listed in pairs above are known to occur (at least at times) in comparatively deep water. 

 With regard to the fishes of the last category, the families of special importance are 

 the following: Muraenolepidae, Bovichthyidae, Nototheniidae, Chaenichthyidae and 

 Zoarcidae. Regan 1 has already dealt with these in his discussion of the Magellan 

 district, and his conclusions, with very slight modifications, have been confirmed by 

 my own work. 



Muraenolepidae. Muraenolepis orangiensis is confined to the Patagonian region. 

 M. microps occurs on the Burdwood Bank, south of the Falkland Islands and also at 

 South Georgia, the South Sandwich Islands, and off new land south of the Balleny 

 Islands. A third species, M. marmoratus, is found at Kerguelen. 



Bovichthyidae. The genus Cottoperca is characteristic of this region, but the single 

 species extends northwards on the coast of Argentina. A species of Bovichthys (B. 

 argentiniis) has recently been described from the Golfo Nuevo (just south of the San 

 Jose Peninsula) and from the Golfo San Jorge (about latitude 46 S). 



Nototheniidae. The characteristic Antarctic genera Trematomus and Pleuragramma, 

 and the Harpagiferinae, except Harpagifer bispinis, are absent. Eleginops maclovinus 

 ranges northwards to Valparaiso on the west coast and to Buenos Aires on the east. 

 Dissostichus eleginoides ranges northwards on the coast of Argentina to the Rio Plata 

 and southwards to Graham Land. What has been described by Regan as the tessellata 

 group of Notothenia, a natural group of eleven species, comprising all those with the 

 upper surface and sides of the head, except the snout and the praeorbital, scaled, and 

 with a rather broad interorbital region, is peculiar to this area. Two species of another 

 type, with the opercles scaled on the upper part of the operculum only, and with the 

 upper surface of the head naked (N. comucola, N. elegans), are not found elsewhere, 

 and two other species of the same group but with a reduced number of anal rays 

 (N. macrocephala, N. microlepidota) occur also in the Antipodes district. Finally, there 

 is one species (N. macrophthalma) from near the Burdwood Bank, which has not been 

 recorded elsewhere but which is very closely related to N. sqiiamifrons from Kerguelen. 

 Chaenichthyidae. Represented in this region by Champsocephaliis esox. This species 

 does not occur elsewhere, but the genus contains one other species from South Georgia. 

 Zoarcidae. Ilnocoetes and Austrolycus each have one species peculiar to the region 

 and another which appears to extend northwards along the coast of Argentina. 

 Phucocoetes (1 species), Crossostomus (2 species) and Pogonolyciis (1 species) are peculiar; 

 the single species of Platea extends northwards on the Argentine coast. Ophthalmolycus 

 has one species here and one in the Antarctic, and Maynea has two here and one in 

 the Antarctic. 



1 1914, Rep. Brit. Antarct. (' Terra Nova') Exped. 1910, Zool. I, p. 37. 



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