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a very well-marked Sub-region, in which the terrestrial mammals, though not very numerous, nearly all belong to peculiar genera.
The higher ranges of the Andes from Ecuador southwards, together with the pampas of Southern Argentina and Patagonia, form another well-marked Sub-region characterised by a number of peculiar genera and species. But the whole remainder of the Neotropical Region from Mexico to Southern Brazil contains, so far as we understand it at present, a more or less homogeneous mammalfauna, of which, however, the northern half possesses a considerable admixture of Nearctic forms, while the southern preserves a more purely indigenous facies. It will, therefore, be quite in accordance with the facts of nature, as well as convenient, to separate the northern portion of this extensive area as the Central American (or Transpanamanic) Sub-region. But as regards the southern portion, until our knowledge of the distribution of South American mammals has made greater progress, it seems best to unite the Colombian, Amazonian, and Brazilian Subregions of the Ornithologists into one combined Sub-region, which may be called the Guiano-Brazilian Sub-region.
We shall thus have, as regards Mammals, four Subregions of the Neotropical Region, as follows (see Map, Plate III., p. 82) :—
1. The Antillean Sub-region, comprising the whole of the West India Islands except Curacao, Trinidad, and Tobago.
2. The Central-American Sub-region, comprising the low-lying and southern parts of Mexico and Central America as far as the Isthmus of Panama.
3. The Guiano-Brazilian Sub-region, comprising the greater part of South America from the Isthmus of Panama to the southern limits of the great forest in about lat. 30° S., and from the forest of the eastern slopes of the Andes to the Atlantic, including Trinidad and the other islands off the coast of Venezuela.
4. The Patagonian Sub-region, comprising the higher ranges and western slopes of the Andes from Guyaquil to Tierra del Fuego and the pampas of Argentina and Patagonia.
Section IV.—The Antillean Sub-region
The Mammal-fauna of the Antillean Sub-region is exceedingly poor, so poor, indeed, that it seems almost doubtful whether the islands of which it is composed have ever been directly connected with the mainland of America as at present constituted. To begin with the Rodents, four genera of this order are represented within its limits, and three of these are restricted to the Sub-region. Megalomys (a large rat, over twelve inches in length without the tail) is allied to the Vesper-mice of the American continent, and has been obtained only in the islands of Martinique and St. Lucia, where it is now becoming very rare (10). A more important factor in the Antillean mammal-fauna is Capromys, a genus allied, according to Flower and Lydekker, to the Coypu rat of South America, but also showing some affinities to the Porcupines. There are five or six species of this genus usually recognised, of which two or three are restricted to Cuba, one is peculiar to Jamaica, and one to the Bahamas, while another species has been recently discovered in Swan Island, situated in the middle of the Gulf of Mexico. An allied genus (Plagiodon) with one species, differing from Capromys only in a slight modification of the teeth, is found in Hayti. It is obviously derived from the same stock. A peculiar species of agouti (Dasyprocta cristata) is found in two of the Lesser Antilles—St. Vincent and St. Thomas; the other members of this genus belong to the mainland of Central and South America. The only other Order of terrestrial Mammals represented in this Sub-region is the Insectivora, and this is the more remarkable because, as already shown, one of the special characters of the Neotropical Region is the almost complete absence of this group within its limits. The West Indian representatives of this group are two in number, and belong to a peculiar genus (Solenodon), which is of rather doubtful affinities but of family rank. It is allied in some respects to the moles (Talpidm), and in others to a peculiar Malagasian family, the Tenrecs (Centetidm). The Solenodonts are small creatures with a somewhat shrew-like aspect, a long snout, and a long naked tail. There are two representative species of this genus confined to the islands of Hayti and Cuba respectively.
The Bats of the Antillean islands, as would naturally be expected, are somewhat more abundant than the terrestrial mammals. There have been recorded by naturalists about thirty species belonging to some twenty genera as found in the different islands, the greater number being from Cuba and Jamaica. On examining the list, it will be found that of these twenty genera three only seem to be confined to the West Indian Region, while thirteen are spread over the greater part of theNeotropicalRegion.one belongs to the Nearetic Region, and the others are of wider distribution.
The evidence of the Bats, therefore, points unmistakably to the inference that the West India Islands have been peopled with Mammalian life from South and not from North America. In this connection it may be noted that Mr. Frank Chapman in an instructive article (4) on the origin of the West Indian fauna, recently published, has stated, as regards the birds, that the total number as yet recorded as met with within the limits of this Sub-region amounts to 550. Of these 303 are endemic, while the
remaining 247 may be allotted to the countries from which they have been apparently derived as follows:—
Common to Xorth and South America .... 16
in the Greater Antilles) 13
Central American 3
North American (all annual migrants from the north,
This summary gives us a clue to the origin of the more recent additions to the West Indies fauna, which is obviously by migration from the north. If, however, the relationships of the 303 endemic species of Birds are examined, it will be at once evident that they are all more closely allied to South American than to North American forms, and, like the Bats, show that the islands have been stocked with life from the south. Moreover, Mr. Chapman, as well as Mr. Wallace, has pointed out that nearly all the more distinct and most characteristic West Indian Birds are found in the Greater Antilles (i.e. Cuba, Hayti, Porto Rico, and Jamaica), and that the Lesser Antilles form a distinct group, the line of separation between the two provinces coinciding nearly with the deep channel between the Virgin Islands on the west, and the Anguilla group on the east.
On the whole the Lesser Antilles appear to have derived their fauna direct from South America, but probably in times considerably remote, and without the assistance of a land-connection. The almost complete absence of terrestrial mammals and of representatives of sedentary and non-migratory birds in the Lesser Antilles seems to show this. For instance, Grenada possesses only fifteen land-birds also found in Trinidad, and of these none belong to the sedentary families, although the two islands are only separated by an interval of seventy-five miles of sea. On the whole, therefore, it seems probable that, although the Lesser Antilles have derived the bulk of their fauna from South America, they have never been directly connected with that continent.
Of the Greater Antilles, Jamaica and Cuba have by far the richest endemic faunas, whereas in Hayti and Porto Rico the total number, as well as the number of endemic species, is considerably smaller. Jamaica, therefore, with its small area (one-tenth of that of Cuba, one-eighth of that of Hayti, and a little more than that of Porto Rico), and in spite of its more isolated position, contains on the whole, so far as our present knowledge goes, the richest fauna.
This may, perhaps, be explained by the fact that between the north-east corner of Honduras and Jamaica there stretches a series of more or less shallow banks, so that a comparatively slight elevation of the intervening seabottom would very nearly connect Jamaica with the mainland.
Whether such a complete land-connection (or only an