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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 (Talpidæ), and in others to a peculiar Malagasian family, the Tenrecs (Centetidæ). 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 the Neotropical Region,one belongs to the Nearctic 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 North and South America
in the Greater Antilles)
through Florida, and the larger proportion found in
160 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
approximation of land areas) by this route ever existed, cannot at present be definitely settled. On the one hand, as pointed out by Mr. Chapman, the disproportionately rich fauna of Jamaica, the shallow sea, and the West Indian affinities of Swan Island (as shown by the presence of a species of Capromys) lead to such a direct connection. On the other hand, the scarcity of land-mammals in Jamaica and Cuba, and the absence of many families of Birds found on the mainland, rather point the other way. The help in these questions to be derived from paleontology is up to this time very scanty. Almost the only remains of fossil mammals that have been yet obtained from the West Indies are certain detached teeth and some fragmentary bones, found in some caves in the island of Anguilla, which is situated just to the east of the deep channel separating the Greater from the Lesser Antilles, and must, therefore, be included in the latter province. These remains have been described by Professor Cope (5), who considers then to be related to the Chinchillas, a family of rodents confined to South America.
The nature of the Mammalian genera of the Antillean Region is summarised in the subjoined table :
SECTION V.-THE CENTRAL AMERICAN SUB-REGION
This Sub-region, as has been already shown, contains the coast-lands of Mexico lying along the Pacific and Atlantic shores from Mazatlan on the north on one side, and from the Rio Grande on the other, together with the whole of Central America from the Isthmus of Tehuantepec to that of Panama.
As regards the fauna of this part of America, we are fortunate in being able to refer to the excellent account of it contained in the“ Biologia Centrali-Americana” of Messrs. Salvin and Godman. The volume relating to the mammals in this work was undertaken by Mr. Alston, and finally completed after his death by one of the authors of this work in 1882 (3). Out of a total of sixty-nine genera of mammals represented in this Sub-region, only two seem to be absolutely restricted to it, and these, moreover, are genera of bats, which may possibly be found at some future time to extend into the main South American continent.
Of the sixty-seven non- peculiar Central - American genera of mammals, forty-one are Neotropical typesthat is, found also in one or more of the other Sub-regions of this Region-five are Nearctic, nine are found both in the Nearctic and in other Sub-regions of the Neotropical Region, and twelve are cosmopolitan, or, at any rate, found in some part of the Old World as well as in the New.
These facts show conclusively the thoroughly Neotropical character of the Central-American Sub-region, which, although the admixture of northern forms has really made very little progress, may be defined as that part of the Neotropical Region which has been subjected to an incursion of Nearctic types.