Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/768

Rh 750 BIRDS DISTRIBUTION. Cuba; and thus we have afforded us another case of interrupted generic distribution somewhat like though not quite so extraordinary as that of Certhiola already noticed. In all, about 17 species of Trochilidce are found in the Antilles, of which only one, and that of exceptionally developed migratory habits, occurs elsewhere. The pecu liar family Todidas has been already mentioned ; and it is only necessary here to remark that the single genus Todus which it contains seems to have 5 species, one limited to each of the large islands, Cuba, Jamaica, Hispaniola, and Porto Rico, the fifth being from an unknown locality. 1 Much the same has to be said of Saurothcra, a genus of Cuculidce, which is represented by a distinct species in each of these four islands, while another genus of the same family, Hyetornis, with one species, is peculiar to Jamaica. The Trogonidce have two genera, Prionotdes and Temnotrogon, each with a single species, the former peculiar to Cuba, and the latter, which exhibits a remarkable affinity to the African genus Hapaloderma, to Hispaniola. Pseudoscops, a genus of Strigidce, is peculiar to Jamaica, but Gymnoglaux, belonging to the same family, has one species limited to Cuba, while a second extends from Porto Rico to some of the Virgin Islands. Cuba also, besides a widely-ranging species of Kestrel (Tinnunculus), has a second species which is peculiar to the island. Jamaica, on the other hand, seems to have no Kestrel at all. Any speculations as to the former history of the Antilles derived from our imperfect knowledge of their existing ornis would be vain. It is enough to perceive, as the preceding facts will show, that there must here have been no ordinary amount of upheaval and subsidence, of turning land into water and water into land, to account for the present distribution of their avifauna. More wonderful than any evidence given by the Birds, is that which is afforded by other Classes. It is asserted that /Solenodon, an Antillean genus of Insectivorous Mammals, has its nearest ally in a Malagasy form ; and a splendid Butterfly, found only in Jamaica (Urania sloanii), belongs to a genus of which while two other species are known from Central and South America respectively, the only other genus re sembling it is one that inhabits Madagascar. KARCTIC III. THE NEARCTIC REGION comprises all that is left of
 * GIOX. the American continent, after the Neotropical Region has

mud- been taken off, and certain outlying groups of islands, such ies. as the Aleutian chain, with its immediate dependencies, and the Bermudas none of them, however, being of any great importance, as well as the circumpolar lands lying westward of long. 60 W., and Greenland. The confines of these two Regions, as before stated (page 748), are as yet but vaguely traced. All that is known for certain is that the more northern runs considerably southward along the highlands of Central America, and that its influence, as determined by the presence of resident genera of northern extraction, is perceptibly felt on the summits or slopes of the mountains, at least so far southward as lat. 20 N. In the lowlands the boundary lies much further towards the north, and, perhaps, in general terms, may be placed somewhere about lat. 25 N., while both in lowlands and highlands, as above explained, the northern influence varies with the seasons of the year, being greatest in winter, when the migratory birds, which breed in the Nearctic Region, have turned their flight southward, and least in summer, when they have retired to their northern eneral homes. If the avifauna of the Neotropical Region could, iaracter- i n a wide sense, be truly termed homogeneous, much more is this the state of the case with the Nearctic. Of the 63 families 2 of Birds, which is the highest number 1 A &quot;bird of this group was one of those asserted by Ledra to have formerly occurred in St Thomas (page 734). that it seems possible to count for this region, only 1, CJiamccidce, is peculiar, and the validity of the grounds on which this has been established as such may be open to question; 44 of them are also Paltsarctic; and the remaining 18 are common to the Neotropical Region, of which last number at least 4 (Trogonidce, Plot idee, Fregatidce, and Phaetontidce) have a much more extended range. Thus there are 14 peculiarly American families left. These are Mniotiltidce, Coerebidce, Tanagridce, Virc- onidce, Icteridce, Tyrannidce, Trochilidce, Momotidce, Aridce, Cathartidce, Cracidce, Mdeagridce, Tantcdidce, and Aramidce. But the propriety of here admitting Trogonidce (mentioned above) and Momotida is very doubtful ; for, though included by Dr Coues, they are omitted by Professor Baird from his North American Birds, the most recent work on the subject. The claim of Coerebidce to be con sidered Nearctic is also slender, resting on the fact that a small colony of the Sugar-bird which inhabits the Bahamas (Certhiola bahamensis) has established itself on one of the Florida Cays. The Aridce are represented in the Region by a single species only the long-known Carolina Parra- keet (Conurus carolinensis) ; and the Tanagridae, a family containing upwards of forty genera, have but one genus (Pyrangd), exemplified by four or five species, out of about a dozen, which occur within its limits. On the other hand, the peculiarly American families best represented in the Nearctic Region seem to be four in number, Mniotiltidce, by 13 genera and about 50 species, Vireonidce by 1 genus and 14 species, Icteridce by 8 genera and 21 species, and Tyrannidce by 8 genera and 26 species. The first of these, however, can alone be re garded as eminently characteristic of the Region, since that affords a home to all but 3 of the genera, but at the same time, only about one-half of the described species occur there. None of the rest can compare with it in this respect, Vireonidce having 5 genera and 50 species, Icte ridce 24 genera and 105 species, and Tyrannidce 71 genera and 324 species in the Neotropical Region. Coming now to the genera of Nearctic birds, we may put the number perhaps at 330, of which 24 seem to be peculiar to the Region ; 2 of them belong to Turdidce, 1 to Chamceidce, Parities, Troglodijtidce, and Motacillidce respectively, 5 to Emberizidce, 2 to Corvidae, 1 to each of Picidce, Falconiclce, and Columbidce, 5 to Tetraonidce, and 1 to Scolopacidce, Anatidce, and Laridce respectively. But it is perhaps worth remarking that the families Emberizidce and Tetraonidce, here most abundantly represented by genera, are still more abundantly represented in like manner else where. In the Neotropical Region we have some 30 and Rekil in the Old World some 15 genera of the former, which are to t not found in the Nearctic Region ; and the Old World has R&amp;lt; some 30 genera of the latter which are not found in the New. On the other hand it must be admitted that if we subdivide the American Tetraonidce into sections or sub families, we find that while one of those sections, the Odon tophorince, is peculiar to America, the balance as regards the other, Tetraonince, is clearly in favour of its greater development in North America, where we have 3 genera absolutely peculiar, as well as 3 others which are also found in the Pabearctic Region. With this Region, indeed, the Nearctic has about 128 genera in common, having 178 which are also Neotropical. Returning to these last pre sently, it may be advisable here to give some particulars of those which are common to both sides of the North Atlantic. 1 belongs to each of the families Turdidce and Cindidce ; 3 to Sylviidce, 2 to Paridce, 1 to Sittidce, Ccrthiidce, Troglo- dyticlce, and Alaudidce respectively, 2 to each of Mota- id(r) are not regarded as good families by the writer, common also to the Palaearctic Region. They are all
 * Three of these (Hcematopodidae, Recurvirostridce, and Plialaropod*