If we draw a line immediately south of St. Croix and St. Bartholomew, we shall divide the Archipelago into two very different groups. The southern range of islands, or the Lesser Antilles, are, almost without exception, volcanic; beginning with the small detached volcanoes of Saba and St. Eustatius, and ending with the old volcano of Grenada. Barbuda and Antigua are low islands of Tertiary or recent formation, connected with the volcanic islands by a submerged bank at no great depth. The islands to the north and west are none of them volcanic; many are very large, and these have all a central nucleus of ancient or granitic rocks. We must also note, that the channels between these islands are not of excessive depth, and that their outlines, as well as the direction of their mountain ranges, point to a former union. Thus, the northern range of Hayti is continued westward in Cuba, and eastward in Portorico; while the south-western peninsula extends in a direct line towards Jamaica, the depth between them being 600 fathoms. Between Portorico and Hayti there is only 250 fathoms; while close to the south of all these islands the sea is enormously deep, from more than 1,000 fathoms south of Cuba and Jamaica, to 2,000 south of Hayti, and 2,600 fathoms near the south-east extremity of Portorico. The importance of the division here pointed out will be seen, when we state, that indigenous mammalia of peculiar genera are found on the western group of islands only; and it is on these that all the chief peculiarities of Antillian zoology are developed.
Mammalia.—The mammals of the West Indian Islands are exceedingly few, but very interesting. Almost all the orders most characteristic of South America are absent. There are no monkeys, no carnivora, no edentata. Besides bats, which are abundant, only two orders are represented; rodents, by peculiar forms of a South American family; and insectivora (an order entirely wanting in South America) by a genus belonging to a family largely developed in Madagascar and found nowhere else. The early voyagers mention "Coatis" and "Agoutis" as being found in Hayti and the other large islands, and it is not improbable that species allied to Nasua and Dasyprocta did exist, and have been destroyed by the dogs of the invaders; though, on the other hand, these names may have been applied to the existing species, which do bear some general resemblance to these two forms.
The Chiroptera, or bats, are represented by a large number of species and by several peculiar genera. The American family of Phyllostomidæ or vampires, has six genera in the Antilles, of which three, Lonchorina, Brachyphylla, and Phyllonycteris, are peculiar, the latter being found only in Cuba. The Vespertilionidæ have four genera, of which one, Nycticellus, is confined to Cuba. There are six genera of Noctilionidæ, of which one, Phyllodia, is confined to Jamaica.
The Insectivora are represented by the genus Solenodon, of which two species are known, one inhabiting Cuba the other Hayti. These are small animals about the size of a cat, with long shrew-like snout, bare rat-like tail, and long claws. Their peculiar dentition and other points of their anatomy shows that they belong to the family Centetidæ, of which five different genera inhabit Madagascar; while there is nothing closely allied to them in any other part of the world but in these two islands.
Seals are said to be found on the shores of some of the islands, but they are very imperfectly known.
The rodents belong to the family Octodontidæ, or, according to some authors, to the Echimyidæ, both characteristic South American groups. They consist of two genera, Capromys, containing three or four species inhabiting Cuba and Jamaica; while Plagiodontia (very closely allied) is confined to Hayti. A peculiar mouse, a species of the American genus Hesperomys, is said to inhabit Hayti and Martinique, and probably other islands. A Dasyprocta or agouti, closely allied to, if not identical with, a South American species, inhabits St. Vincent, St. Lucia, and Grenada, and perhaps St. Thomas, and is the only mammal of any size indigenous to the Lesser Antilles. All the islands in which sugar is cultivated are, however, overrun with European rats and mice, and it is not improbable that these may have starved out and exterminated some of the smaller native rodents.
Birds.—The birds of the Antilles, although very inferior in number and variety to those of the mainland, are yet sufficiently abundant and remarkable, to offer us good materials for elucidating the past history of the country, when aided by such indications as geology and physical geography can afford.
The total number of land-birds which are permanent residents in the West India islands is, as nearly as can be ascertained from existing materials, 203. There are, in addition to this number, according to Prof. Baird, 88 migrants from North America, which either spend the winter in some of the islands or pass on to Central or South America. These migrants belong to 55 genera, and it is an interesting fact that so many as 40 of these genera have no resident representatives in the islands. This is important, as showing that this northern migration is probably a recent and superficial phenomenon, and has not produced any (or a very slight) permanent effect on the fauna. The migratory genera which have permanent residents, and almost always representative species, in the islands, are in most cases characteristic rather of the Neotropical than of the Nearctic fauna, as the following list will show; Turdus, Dendrœca, Vireo, Polioptila, Agelæus, Icterus, Contopus, Myiarchus, Tyrannus, Antrostomus, Chordeiles, Coccyzus, Columba. By far the larger part of these birds visit Cuba only; 81 species being recorded as occurring in that island, while only 31 have been found in Jamacia, 12 in Porto Rico and St. Croix, and 2 in Tobago and Trinidad. Setting aside these migratory birds, as having no bearing on the origin of the true Antillean fauna, we will discuss the residents somewhat in detail.
The resident land-birds (203 in number) belong to 95 genera and 26 families. Of these families 15 are cosmopolitan or nearly so—Turdidæ, Sylviidæ, Corvidæ, Hirundinidæ, Fringillidæ, Picidæ, Cuculidæ, Caprimulgidæ, Cypselidæ, Trogonidæ, Psittacidæ, Columbidæ, Tetraonidæ, Falconidæ, and Strigidæ; 5 are American only—Vireonidæ, Mniotiltidæ, Icteridæ, Tyrannidæ, Trochilidæ; 4 are Netropical only or almost exclusively—Cœrebidæ, Tanagridæ, Cotingidæ, Conuridæ; 1 is Antillean only—Todidæ; while 1—Ampelidæ—is confined (in the western hemisphere) to North America, and almost to the Nearctic region. Of the 95 genera, no less than 31, or almost exactly one-third, are peculiar; while of the 203 resident species, 177 are peculiar, the other 26 being all inhabitants of South or Central America. Considering how closely the islands approach the continent in several places—Florida, Yucatan, and Venezuela—this amount of speciality in such locomotive creatures as birds, is probably unexampled in any other part of the globe. The most interesting of these peculiar genera are the following: 4 of Turdidæ, or thrushes—1 confined to the large islands, 1 to the whole archipelago, while 2 are limited to the Lesser Antilles; 2 genera of Tanagridæ, confined to the larger islands; 2 of Trogonidæ, also confined to the larger islands; 5 of hummingbirds, 3 confined to the Greater, 1 to the Lesser Antilles; 2 of cuckoos, one represented in all the large islands, the other in Jamaica only; 2 of owls, one peculiar to Jamaica, the other represented in St. Croix, St. Thomas, Portorico, and Cuba; and lastly, Todus, constituting a peculiar family, and having representative species in each of the larger islands, is especially interesting because it belongs to a group of families which are wholly Neotropical—the Momotidæ, Galbulidæ, and Todidæ. The presence of this peculiar form, with 2 trogons; 10 species of parrots, all but one peculiar; 16 peculiar humming-birds belonging to 8 genera; a genus of Cotingidæ; 10 peculiar tanagers belonging to 3 genera; 9 Cœrebidæ of 3 genera; together with species of such exclusively Netropical genera as Cœreba, Certhiola, Sycalis, Phonipara, Elainea, Pitangus, Campephilus, Chloronerpes, Nyctibius, Stenopsis, Lampornis, Calypte, Ara, Chrysotis, Zenaida, Leptoptila, and Geotrygon, sufficiently demonstrate the predominant affinities of this fauna; although there are many cases in which it is difficult to say, whether the ancestors of the peculiar genera or species may not have been derived from the Nearctic rather than from the Neotropical region.
The several islands differ considerably in their apparent productiveness, but this is, no doubt, partly due to our knowledge of Cuba and Jamaica being much more complete than of Hayti. The species of resident land-birds at present known are as follows:—