4 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



In the present report only such species are included as have been defi- 

 nitely recorded from within the geographical limits of the region here 

 under consideration. Possibly a few already recorded have been over- 

 looked. However that may be, doubtless many described from points 

 further north will be fqund to extend into it, and probably some, not here 

 included, described from the coast district of southern Chili, will be found 

 to extend southward and eastward into Patagonia. 



As very few of the species of this region have been adequately figured, 

 as regards the skull and dentition, advantage is taken of the present oppor- 

 tunity to publish illustrations of the cranial and dental characters of a 

 considerable number of species, particularly among the Rodents, to serve 

 as standards of comparison in considering allied forms. 



As regards the general facies of the Patagonian land mammal fauna, the 

 paucity of types is noteworthy, due to the high southern latitude of the 

 region. It is of course far beyond the range of monkeys and marsupials, 

 while bats, of one or two species, barely reach its northern border. The 

 families Leporidae, Dasyproctidas, and Sciuridae are absent, and the 

 Ruminants are represented by the Guanaco, this region being its metrop- 

 olis, and by a single species of deer. The Mustelidae are represented by 

 three genera, Conepatits, Lyncodou, and Liifra, while the Canidae and 

 Felidae have each several species. A single species of Armadillo is found 

 as far south as the Rio Santa Cruz. There are two representatives of the 

 Caviidae, and the family Chinchillidae is represented by one of its three 

 genera. The abundant genus Ctenomys alon€ represents the Octodon- 

 tidae ; but the region may be said to be the headquarters of the Murine 

 genera ReitJirodon and Euneouiys. Its other characteristic genera of 

 Muridae are Akodon, Oxymycterus, Pliyllotis, and Eligniodotitia, while 

 the wide ranging genus Oryzomys has here a few outlying species. The 

 only murine genus peculiar to the region is Ahtiomys, known thus far by 

 a single specimen taken near Santa Cruz, nearly twenty years ago, by the 

 French Mission Scientifique du Cap Horn. 



The shores and outlying islands of Patagonia were formerly great 

 resorts of antarctic types of Pinnipedia, representatives of which still exist, 

 but in greatly reduced numbers, including of the Otariidae, the genera 

 Otaria and Arctocephalus, and of the Phocidae the genera Mirottnga, 

 HydrjiygHS, Leptonychotes and Lobodon. 



During the preparation of this work several new forms have been dis- 



