350 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



respectively termed the Andean and Pampean. The Andean Prov- 

 ince is principally characterized by the presence of Ursiis (Tremarctus) 

 ornatus, the genera Fudu, Furcifer, Tolypeutes, CMamydo;pJiorus, CTiin- 

 ehilla, Lagidium, Spalaco;pus, Sabrooomus, and Octodon. Auchenia and 

 several genera of Rodents range from the Andean Province south- 

 ward over the plains of Patagonia to Tierra del Faego. The Pata- 

 gonian x^lains share largely in the general fades of the Andean fauna. 

 A few genera only are restricted to the Pampean Province, these being 

 mainly Ctenomys, Lagostomus, and DoUchotis. The differences between 

 these two provinces relate mainly to species rather than to genera. The 

 Pampean Province is much the smaller, embracing only the compara- 

 tively level pampa district bordering the La Plata and Lower Parana 

 Eivers. So little is definitely known respecting the range of the mam- 

 mals of this general region that it is scarcely practicable to attempt at 

 present a definition of the boundaries between the Pampean and An- 

 dean divisions. 



The relation of the South Temperate American to the Tropical Amer- 

 ican Eealm is of course far closer than to any other, there being as 

 usual a gradual transition between the two along their line of junction, 

 through the extension of a few, forms characteristic of the one for a 

 short distance into the other, just as has been observed to be the case 

 between the North Temperate and Tropical American Eealms. It has,, 

 however, nothing in common with the North Temperate American 

 Eealm beyond the presence of a few cosmopolite types that extend 

 across the intermediate Tropical Eealm. So far as land mammals are 

 concerned, it has no genera common to the South Temperate portions 

 of the Old World, except a few that are almost cosmopolite. The case 

 is different, however, with the marine species. Of the half dozen or 

 more genera of Pinnipeds (the only marine forms we are here called 

 upon to consider), none are peculiar to the shores of Temperate South 

 America but are common to South Temperate and Antarctic shores 

 generally. None of them, however, occur north of the tropics,* and it 

 is hence only through these that there is any closer affinity between 

 the mammalian life of this region and the South Temperate Zone gen- 

 erally than between it and that of north-temperate latitudes. 



Of the thirty-four land genera below enumerated as occurring in the 

 South American Temperate Eealm, rather more than one-half (eighteen) 

 are nearly or wholly confined to it. Most of the remainder extend far 

 to the northward into Tropical America, and others reach North Amer- 

 ica, while five are almost cosmopolitan. 



* Otaria alone reaches the Galapagos, which, although situated nuder the equator,^ 

 are still within the influence of the cold Peruvian current, and appear to constitute an. 

 outlying element of the South American Temperate Realm. 



