Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/724

Rh AMERICA [ZOOLOGY. many instances this sub-region is parcelled out into districts by the larger streams, which are characterised by distinct species. Hence it is probable that the continuousness of the forest area has lasted throughout the duration of those species, but not so long as the genera have existed ; and that those species which occur on both sides of the Amazon, Rio Negro, and other large rivers, originated at an earlier period than those restricted to one side. The want of means of communication with North America would account for the absence of monkeys in that region. Our space will not allow of our dwelling so fully on the other orders, but we may notice that the arboreal habit is strongly marked in many, and that the strictly arboreal groups are frequently represented in river-bounded areas by distinct species, It often happens that genera, both of vertebrates and invertebrates, which are elsewhere terrestrial, are represented in the Amazonian forests by arboreal species. TheCarnivoradonot present so marked a feature as regards distribution as the monkeys. The families Felidce, Canidae, Mustelidse, and Ursidae are represented ; but the Hysenidaa and Viverridse are absent, unless Bassaris of Mexico be referred to the latter family. The Felida3 comprise two groups, one formed of species which are uniformly coloured, the other of those which are striped or spotted. Felis onca, the jaguar, is the largest feline animal of this region, and ranges from La Plata to Louisiana, and on both sides of the Peruvian Andes. The puma or F. concolor is known everywhere from Patagonia to as far as 50 or 60 N., a range from north to south of about 1 1 0, which is probably greater than that of any other mammal. F. payeros occurs on all the pampas of the southern portion of South America. F. mitis and F. macrura belong to South-East Brazil ; F. tigrina and celidogaster to the Amazon basin ; while F. pardalis, F. eyra, and F. yagouaToundi range from Brazil to Texas. The Canidas family is represented by the genera Icticyon and Canis. The former comprises but one species, which is confined to Brazil, viz., /. venaticus, which is an aberrant form between dogs and badgers. The dogs com prise C. julatiis, C. cancrivorus, C. vetulus, C. fulvicaudus, G. azarce, C. magellanicus, and one or two other species. The Mustelidse are not abundant, there being only a few species of each of the sub-families Mustelince, Lutrince, and Melince; and among others Mustela frenata ; two species of Galictis, a genus only found in this region; Lutra chilensis and braziliensis; and several species of Mephitis belonging to the sub-genus Thiosmus. Of Ursidse there occur Ursus ornatus in Peru, and perhaps Ursus frugilegus ; Frocyon cancrivorus, Nasua, and Cercoleptes. The last two genera are characteristic of South America. In this order the species, with the exception of a few which range into North America, are restricted to this area ; but only four of the eleven genera are peculiar, the others ranging not only into North America, but also into the Old World. The latter genera do not form a prominent feature in the fauna, and the species have probably migrated from North America in comparatively recent times from a geological point of view. In the order Artiodactyla the sub-order Ruminantia is represented by a few species only of Cervus, belonging to the neotropical sub-genera Furcifer, Coassus, and Blastocerus, and even these only occur sparingly in the open tracts. There is nothing to represent the enormous herds of Antelopes and Bovidae, which are so characteristic of North America and portions of the Old World. Auchenia, how ever, is a characteristic genus frequenting the Andes, and is interesting on account of its being the only genus of Ruminants which is confined to South America. It is isolated and far distant from the other members of the family Camelidse, which are now special to Asia ; but, as we shall presently find, the gap in distribution and structure is supplied by the extinct species of North America. The characteristic genus Dicotyles is the sole representative in South America of the sub-order Omnivora and of the family Suidse, a family which is restricted (naturally) to the Neotropical, ^Ethiopian, and Indian regions. Another remarkable genus is Tapirus, which represents in this region the elephants and rhinoceroses of the Old World. Until recently, the tapirs of Sumatra and the Malay Archipelago were considered to belong to the same genus, but Dr Gray has proposed that the latter be ranked in a distinct genus, Rhinochcerus. There are several species of South American tapirs, viz., T. americanus, T. villosus, T. Laurillardii, T. Roulinii, and perhaps one or two others not determined. An allied form exists in the isthmus of Panama, namely Elasmognathus Bairdii, which is considered as the type of a distinct sub-family. There are no true Proboscideans in this region. The order Sirenia is represented by the genus Manatus, of which three or four species occur in the Amazon and other large rivers. This genus is remarkable for its distribution, since species belonging to it frequent the fresh water streams of the opposite coast of Africa. Several species of dolphins and porpoises occur in the larger rivers ; some of them range up almost to their sources, and are strictly river species, being unknown in the adjoining seas. The presence of these cetaceans, together with the distance of the shores (several miles) and the high waves, impart to some portions of these rivers a more or less oceanic aspect. The order Bruta is abundantly represented in this region, of the fauna of which it constitutes the most marked peculiarity. Marsupialism is not a prominent feature in this region, but its presence is important, because it now occurs nowhere else out of. the Australian region. It should be observed that the connection is stronger with the extinct marsupial fauna of Palsearctic regions than with the living one of Australia. The fossil and living mammalia of this region seem to indicate that at present our knowledge of the extinct faunas is very fragmentary. This is shown in various v/ays. None of the remains can be definitely assigned to an older period than the Post-Pliocene. The region was essentially the same as at present, zoologically, the same characteristic groups of platyrhine apes, rodents, cats, dogs, edentates, and opossums being represented ; while the catarhine apes, insectivora, oxen, rhinoceroses, and other groups were ex cluded, or at any rate are not known to have existed in it, so that its isolation from the other zoological regions must have commenced before the Post-Pliocene period. The extra ordinary development of large forms allied to the sloths and ant-eaters ; the restriction of the Toxodontia amongst the Post-Pliocene mammals, and of the subungulated Rodents among the living mammals to this region, these and other facts would lead the palaeontologist to believe that the area must have been inhabited by mammals during the periods which preceded the Post-Pliocene, as far back, perhaps, as the Miocene or Eocene. The Toxodontia include the forms of Pachyderms most nearly allied to the Rodents, while the subungulated Rodents are those of the order which approach nearest to the Pachyderms. As both these groups occur here, and here only, we may reasonably expect to find genera partaking of the general features of both orders in beds of an earlier geological age in South America. The principal genera and species found fossil in this region are the following. In the Argentine Confederation we have Macrauchenia patachonica. Glyptodon spinicaudus. clavipes. tuberculatus. pumilio. clavicaudatus. clavatus. asper. elongatu.3. Machairodus neogteus. Felis longifrons. Canis protalopex. avus. Mephitis primjcva. Ursus bonserensis. Myopotamus boiuerensis. anti^uus. Ctenomys bonaerensis. Lagostomus augustidena. Cavia breviplicata.