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The Noctilionidae, or short-headed Bats, are found in every region, but are very unequally distributed. Their head-quarters is the Neotropical region, where most of the genera occur, and where they range from Mexico to Buenos Ayres and Chili, while in North America there is only one species in California. They are unknown in Australia; but one species occurs in New Zealand, and another in Norfolk Island. Several species of Dysopes (or Molossus) inhabit the Oriental region; one or two species being widely distributed over the continent, while two others inhabit the Indo-Malayan Islands. A species of this same genus occurs in South Africa, and another in Madagascar and in the Island of Bourbon; while one inhabits Southern Europe and North Africa, and another is found at Amoy in China. It will be seen therefore, that these are really South American bats, which have a few allies widely scattered over the various regions of the globe. Their affinities are, according to Mr. Tomes, with the Phyllostomidae, a purely South American family. The species which forms the connecting link is the Mystacina tuberculata, a New Zealand bat, which may, with almost equal propriety be placed in either family, and which affords an interesting illustration of the many points of resemblance between the Australian and Neotropical regions. Dr. Peters has separated this family into three-Mormopidae, which is wholly Neotropical, and is especially abundant in the West Indian Islands; Molossidae, chiefly consisting of the genus Molossus; and Noctilionidae, comprising the remainder of the family, and wholly Neotropical. Mr. Dobson, however, classes the Mormopes with the Phyllostomidae, and reduces the Molossi to the rank of a sub-family. In our first volume we have classed Rhinopoma with the Rhinolophidae, and Taphozous with the Vespertilionidae ; but according to Mr. Dobson both these genera belong to the present family.
Remarks on the Distribution of the Order Chiroptera.
Although the bats, from their great powers of flight, are not amenable to the limitations which determine the distribution of other terrestrial mammals, yet certain great facts of distribution come out in a very striking manner. The speciality of the Neotropical region is well shown, not only by its exclusive possession of one large family (Phyllostomidae), but almost equally so by the total absence of two others (Pteropidae and Rhinolophidae). The Nearctic region is also unusually well marked, by the total absence of a family (Rhinolophidae) which is tolerably well represented in the Palaearctic. The Pteropidae well characterize the tropical regions of the Old World and Australia; while the Wespertilionidae are more characteristic of the Palaearctic and Nearctic regions, which together possess about 60 species of this family. The bats are a very difficult study, and it is quite uncertain how many distinct species are really known. Schinz, in his Synopsis Mammalium (1844) describes 330, while the list given by Mr. Andrew Murray in his Geographical Distribution of Mammalia (1866), contains 400 species. A small number of new species have been since described, but others have been sunk as synonyms, so that we can perhaps hardly obtain a nearer approximation to the truth than the last number. In Europe there are 35 species, and only 17 in North America.
Fossil Chiroptera.-The fossil remains of bats that have yet been discovered, being chiefly allied to forms still existing in the same countries, throw no light on the origin or affinities of this remarkable and isolated order of Mammalia; but as species very similar to those now living were in existence so far back as Miocene or even Eocene times, we may be sure the group is one of immense antiquity, and that there has been ample time for the amount of variation and extinction required to bring about the limitation of types, and the peculiarities of distribution we now find to exist.
The singular and isolated genus Galeopithecus, or flying lemur, has been usually placed among the Lemuroidea, but it is now considered to come best at the head of the Insectivora. Its food however, seems to be purely vegetable, and the very small, blind, and naked young, closely attached to the wrinkled skin of the mother's breast, perhaps indicates some affinity with the Marsupials. This animal seems, in fact, to be a lateral offshoot of some low form, which has survived during the process of development of the Insectivora, the Lemuroidea, and the Marsupials, from an ancestral type. Only two species are known, one found in Malacca, Sumatra, and Borneo, but not in Java; the other in the Philippine islands (Plate VIII. vol. i. p. 337).
The Macroscelides, or elephant shrews, are extraordinary little animals, with trunk-like snout and kangaroo-like hind-legs. They are almost confined to South Africa, whence they extend up the east coast as far as the Zambezi and Mozambique. A single outlying species of Macroscelides inhabits Barbary and Algeria; while the two genera Petrodromus, and Rhyncocyon, each represented by a single species, have only been found at Mozambique.
The Tupaiidae are squirrel-like shrews, having bushy tails, and often climbing up trees, but also feeding on the ground and among low bushes. The typical Tupaia (7 species), are called ground squirrels by the Malays. They are most abundant in the Malay islands and Indo-Chinese countries, but one species is found in the Khasia Mountains, and one in the Eastern Ghauts near Madras. The small shorter-tailed Hylomys (2 species) is found from Tenasserim to Java and Borneo; while the elegant little Ptilocerus (1 species) with its long pencilled tail, is confined to Borneo; (Plate VIII. vol. i. p. 337). The family is therefore especially Malayan, with outlying species in northern and continental India.
Eactinct Species.—0aygomphus, found in the Tertiary deposits of Germany, is believed to belong to this family; as is Omomys, from the Pliocene of the United States.
The Hedgehogs, comprised in the genus Erinaceus (14 species), are widely distributed over the Palaearctic, and a part of the Oriental regions; but they only occur in the Ethiopian region in South Africa and in the Deserts of the north, which more properly belong to the Palaearctic region. They are absent from the Malayan, and also from the Indo-Chinese sub-regions; except that they extend from the north of China to Amoy and Formosa, and into the temperate highlands of the Western Himalayas. The curious Gymnura (1 species) is found in Borneo, Sumatra, and the Malay peninsula. Eastinct Species—The common hedgehog has been found fossil in several Post-tertiary deposits, while extinct species occur in the lower Miocene of Auvergne and in some other parts of Europe. Many of these remains are classed in different genera from the living species;–(Amphechinus, Tetracus, Galeria.)
The Centetidae are small animals, many of them having a spiny covering, whence the species of Centetes have been called Madagascar hedgehogs. The genera Centetes (2 species), Hemicentetes (1 species), Ericulus (1 species), Echinops (3 species), and the recently described Oryzorictes (1 species), are all exclusively inhabitants of Madagascar, and are almost or quite tail-less. The remaining genus, Solenodon, is a more slender and active animal, with a long, rat-like tail, shrew-like head, and coarse fur; and the two known species are among the very few indigenous mammals of the West Indian islands, one being found in Cuba (Plate XVII, vol. ii., p. 67), the other in Hayti. Although presenting many points of difference in detail, the essential characters of this curious, animal are, according to Professors Peters and Mivart, identical with the rest of the Centetidae. We have thus a most remarkable and well-established case of discontinuous distribution, two portions of the same family