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Fossil Quadrumana. Not much progress has yet been made in tracing back the various forms of Apes and Monkeys to their earliest appearance on the globe; but there have been some interesting recent discoveries, which lead us to hope that the field is not yet exhausted. The following is a summary of what is known as to the early forms of each family :
Simiidæ.-Two or three species of this family have been found in the Upper Miocene deposits of France and Switzerland. Pliopithecus, of which a species has been found at each locality, was allied to the gibbons (Hylobates), and perhaps to Semnopithecus. A more remarkable form, named Dryopithecus, as large as a man, and having peculiarities of structure which are thought by Gervais and Lartet to indicate a nearer approach to the human form than any existing Ape, has been found in strata of the same age in France.
Semnopithecidæ.—Species of Semnopithecus have been found in the Upper Miocene of Greece, and others in the Siwalik Hills of N. W. India, also of Upper Miocene age. An allied form also occurs in the Miocene of Wurtemburg. Mesopithecus from Greece is somewhat intermediate between Semnopithecus and Macacus.
Remains supposed to be of Semnopithecus, have also occurred in the Pliocene of Montpellier.
Cynopithecido.—Macacus has occurred in Pliocene deposits at Grays, Essex; and also in the South of France along with Cercopithecus.
Cebida.--In the caves of Brazil remains of the genera Cebus, Mycetes, Callithrix, and Hapale, have been found; as well as an extinct form of larger size-Protopithecus.
Lemuroidea.-A true lemur has recently been discovered in the Eocene of France; and it is supposed to be most nearly allied to the peculiar West African genera, Perodicticus and Arctocebus.
Cænopithecus, from the Swiss Jura, is supposed to have affinities both for the Lemurida and the American Cebida.
In the lower Eocene of North America remains have been
discovered, which are believed to belong to this sub-order: but they form two distinct families,-Lemuravidæ and Limnotheridæ. Other remains from the Miocene are believed to be intermediate between these and the Cebidæ,-a most interesting and suggestive affinity, if well founded. For the genera of these American Lemuroidea, see vol. i., p. 133.
General Remarks on the Distribution of Primates. The most striking fact presented by this order, from our present point of view, is the strict limitation of well-marked families to definite areas. The Cebidæ and Hapalidæ would alone serve to mark out tropical America as the nucleus of one of the great zoological divisions of the earth. In the Eastern Hemisphere, the corresponding fact is the entire absence of the order from the Australian region, with the exception of one or two outlying forms, which have evidently transgressed the normal limits of
The separation of the Ethiopian and Oriental regions is, in this order, mainly indicated by the distribution of the genera, no one of which is common to the two regions. The two highest families, the Simiidæ and the Semnopithecidæ, are pretty equally distributed about two equatorial foci, one situated in West Africa, the other in the Malay archipelago,-in Borneo or the Peninsula of Malacca ;-while the third family, Cynopithecidæ, ranges over the whole of both regions, and somewhat overpasses their limits. The Lemuroid group, on the other hand, offers us one of the most singular phenomena in geographical distribution. It consists of three families, the species of which are grouped into six sub-families and 13 genera. One of these families and two of the sub-families, comprising 7 genera, and no less than 30 out of the total of 50 species, are confined to the one island of Madagascar. Of the remainder, 3 genera, comprising 15 species, are spread over tropical Africa; while three other genera with 5 species, inhabit certain restricted portions of India and the Malay islands. These curious facts point unmistakably to the former existence of a large tract of land in what is now the Indian Ocean, connecting Madagascar on the one hand with Ceylon, and with the Malay countries on the
other. About this same time (but perhaps not contemporaneously) Madagascar must have been connected with some portion of Southern Africa, and the whole of the country would possess no other Primates but Lemuroidea. After the Madagascar territory (very much larger than the existing island) had been separated, a connection appears to have been long maintained (probably by a northerly route) between the more equatorial portions of Asia and Africa; till those higher forms had become developed, which were afterwards differentiated into Simia, Presbytes, and Cynopithecus, on the one hand, and into Troglodytes, Colobus, and Cynocephalus, on the other. cordance with the principle of competition so well expounded by Mr. Darwin, we can understand how, in the vast Asiatic and African area north of the Equator, with a great variety of physical conditions and the influence of a host of competing forms of life, higher types were developed than in the less extensive and long-isolated countries south of the Equator. In Madagascar, where these less complex conditions prevailed in a considerable land-area, the lowly organized Lemuroids have diverged into many specialized forms of their own peculiar type; while on the continents they have, to a great extent, become exterminated, or have maintained their existence in a few cases, in islands or in mountain ranges. In Africa the nocturnal and arboreal Galagos are adapted to a special mode of life, in which they probably have few competitors.
How and when the ancestors of the Cebidæ and Hapalidæ entered the South American continent, it is less easy to conceive. The only rays of light we yet have on the subject are, the supposed affinities of the fossil Cænopithecus of the Swiss, and the Lemuravidæ of the North American Eocene, with both Cebidæ and Lemuroids, and the fact that in Miocene or Eocene times a mild climate prevailed up to the Arctic circle. The discovery of an undoubted Lemuroid in the Eocene of Europe, indicates that the great Northern Continent was probably the birthplace of this low type of mammal, and the source whence Africa and Southern Asia were peopled with them, as it was, at a later period, with the higher forms of monkeys and apes.
FAMILY 9.—PTEROPIDÆ. (9 Genera, 65 Species.)
The Pteropidæ, or fruit-eating Bats, sometimes called flyingfoxes, are pretty evenly distributed over the tropical regions of the Old World and Australia. They range over all Africa and the whole of the Oriental Region, and northward, to Amoy in China and to the South of Japan. They are also found in the more fertile parts of Australia and Tasmania, and in the Pacific Islands as far east as the Marianne and Samoa Islands; but not in the Sandwici Islands or New Zealand.
The genera of bats are exceedingly numerous, but they are in a very unsettled state, and the synonymy is exceedingly confused. The details of their distribution cannot therefore be usefully entered into here. The Pteropidæ differ so much from all other bats, that they are considered to form a distinct suborder of Chiroptera, and by some naturalists even a distinct order of Mammalia.
No fossil Pteropidæ have been discovered.
FAMILY 10.-PHYLLOSTOMIDÆ. (31 Genera, 60 Species.)
The Phyllostomidæ, or simple leaf-nosed Bats, are confined to the Neotropical region, from Mexico and the Antilles to the
southern limits of the forest region east of the Andes, and to about lat. 33° S. in Chili. None are found in the Nearctic region, with the exception of one species in California (Macrotus Californicus), closely allied to Mexican and West Indian forms. The celebrated blood-sucking vampyre bats of South America belong to this group. Two genera, Desmodus and Diphylla, form Dr. Peters' family Desmodidæ. Mr. Dobson, in his recently published arrangement, divides the family into five groups :Mormopes, Vampyri, Glossophagæ, Stenodermata, and Desmodontes.
Numerous remains of extinct species of this family have been found in the bone-caves of Brazil.
FAMILY 11.-RHINOLOPHIDÆ. (7 Genera, 70 Species.)
The Rhinolophidæ, or Horse-shoe Bats (so-called from a curiously-shaped membranous appendance to the nose), range over all the Ethiopian and Oriental regions, the southern part of the Palæarctic region, Australia and Tasmania. They are most abundant and varied in the Oriental region, where twelve genera are found; while only five inhabit the Australian and Ethiopian regions respectively. Europe has only one genus and four species, mostly found in the southern parts, and none going further north than the latitude of England, where two species occur. Two others are found in Japan, at the opposite extremity of the Palæarctic region.
The genera Nycteris and Megaderma, which range over the Ethiopian and'Oriental regions to the Moluccas, are considered by Dr. Peters to form a distinct family, Megadermidæ; and Mr. Dobson in his recent arrangement (published after our first