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the musk-sheep, and the woolly rhinoceros, are associated with several other species of rhinoceros and elephant; with numerous civets, now abundant only in warm countries; and with antelopes of several species. We also meet here with a great extension of range of forms now limited to small areas. The Saiga antelope of Eastern Europe occurs in France, where wild sheep and goats and the chamois were then found, together with several species of deer, of bear, and of hyæna. A few extinct genera even come down to this late period, such as the great sabre-toothed tiger, Machairodus; Galeotherium, a form of Viverrida; Palæospalax, allied to the mole; and Trogontherium, a gigantic form of beaver.

We find then, that even at so early a stage of our inquiries we meet with a problem in distribution by no means easy to solve. How are we to explain the banishment from Europe in so short a space of time (geologically speaking) of so many forms of life now characteristic of warmer countries, and this too during a period when the climate of Central Europe was itself becoming warmer? Such a change must almost certainly have been due to changes of physical geography, which we shall be better able to understand when we have examined the preceding Pliocene period. We may here notice, however, that so far as we yet know, this great recent change in the character of the fauna is confined to the western part of the Palearctic region. In caves in the Altai Mountains examined by Prof. Brandt, a great collection of fossil bones was discovered. These comprised the Siberian rhinoceros and mammoth, and the cave hyæna; but all the others, more than thirty distinct species, are now living in or near the same regions. We may perhaps impute this difference to the fact that the migration of Southern types into this part of Siberia was prevented by the great mountain and desert barrier of the Central Asiatic plateau; whereas in Europe there was at this time a land connection with Africa. Postpliocene deposits and caverns in Algeria have yielded remains resembling the more southern European types of the Postpliocene period, but without any admixture of Arctic forms; showing, as we might expect, that the glacial cold did not

extend so far south. We have here remains of Equus, Bos, Antilope, Hippopotamus, Elephas, Rhinoceros, Ursus, Canis, and Hyana, together with Phacochorus, an African type of swine which has not occurred in the European deposits.

It is perhaps to the earlier portion of this period that the Merycotherium of the Siberian drift belongs. This was an animal related to the living camel, thus supporting the view that the Camelida are essentially denizens of the extra-tropical zone.

PLIOCENE PERIOD.

Primates. We here first meet with evidence of the existence of monkeys in Central Europe. Species of Macacus have left remains not only in the Newer Pliocene of the Val d'Arno in Italy, but in beds of the same age at Grays in Essex; while Semnopithecus and Cercopithecus, genera now confined to the Oriental and Ethiopian regions respectively, have been found in the Pliocene deposits of the South of France and Italy.

Carnivora.-Most of the genera which occurred in the PostPliocene are found here also, and many of the same species. Few new forms appear, except Hyænarctos, a large bear with characters approaching the hyænas, and Pristiphoca, a new form of seal, both from the Older Pliocene of France; and Galecynus, a foxlike animal intermediate between Canis and Viverra, from the Pliocene of Eninghen in Switzerland.

Cetacea. Species of Balana, Physeter, and Delphinus occur in the Older Pliocene of England and France, and with these the remains of many extinct forms, Balanodon and Hoplocetus (Balænidæ); Belemnoziphius and Choneziphius (Hyperoodontidae); and Halitherium, an extinct form of the next order-Sirenia, now confined to the tropics, although the recently extinct Rytina of the N. W. Pacific shows that it is also adapted for temperate climates.

Ungulata. The Pliocene deposits are not very rich in this order. The horses (Equida) are represented by the genus Equus; and here we first meet with Hipparion, in which small lateral toes appear. Both genera occur in British deposits of this age.

A more interesting fact for us is the occurrence of the genus Tapirus in the Newer Pliocene of France and in the older beds of both France and England, since this genus is now isolated in the remotest parts of the eastern and western tropics. The genera Rhinoceros, Hippopotamus, and Sus, occur here as in the preceding epoch.

We next come to the deer genus (Cervus), which appears to have been at its maximum in this period, no less than eight species occurring in the Norwich Crag, and Forest-beds. Among the Bovidae, the antelopes, ox, and bison, are the only forms represented here, as in the Post-Pliocene period. Passing on to the Proboscidea, we find three species of elephants and two of Mastodon preserved in European beds of this period, all distinct from those of Post-Pliocene times.

Rodentia. In this order we find representatives of many living European forms; as Cricetus (hamster), Arvicola (vole), Castor (beaver), Arctomys (marmot), Hystrix (porcupine), Lepus (hare), and Lagomys (pika); and a few that are extinct, the most important being Chalicomys, allied to the beaver; and Issiodromys, said to come nearest to the remarkable Pedetes of South Africa, both found in the Pliocene formations of France.

General Conclusions as to Pliocene and Post-Pliocene Faunas of Europe. This completes the series of fossil forms of the Pliocene deposits of Europe. They show us that the presence of numerous large carnivora and ungulates (now almost wholly tropical) in the Post-Pliocene period, was due to no exceptional or temporary cause, but was the result of a natural succession from similar races which had inhabited the same countries for long preceding ages. In order to understand the vast periods of time covered by the Pliocene and Post-Pliocene formations, the works of Sir Charles Lyell must be studied. We shall then come to see, that the present condition of the fauna of Europe is wholly new and exceptional. For a long succession of ages, various forms of monkeys, hyænas, lions, horses, hipparions, tapirs, rhinoceroses, hippopotami, elephants, mastodons, deer, and antelopes, together

cause.

with almost all the forms now living, produced a rich and varied fauna such as we now see only in the open country of tropical Africa. During all this period we have no reason to believe that the climate or other physical conditions of Europe were more favourable to the existence of these animals than now. We must look upon them, therefore, as true indigenes of the country, and their comparatively recent extinction or banishment as a remarkable phenomenon for which there must have been some adequate What this cause was we can only conjecture; but it seems most probable that it was due to the combined action of the Glacial period, and the subsidence of large areas of land once connecting Europe with Africa. The existence, in the small island of Malta, of no less than three extinct species of elephant (two of very small stature), of a gigantic dormouse, an extinct hippopotamus, and other mammalia, together with the occurrence of remains of hippopotamus in the caves of Gibraltar, indicate very clearly that during the Pliocene epoch, and perhaps during a considerable part of the Post-Pliocene, a connection existed between South Europe and North Africa in at least these two localities. At the same time we have every reason to believe that Britain was united to the Continent, what is now the German Ocean constituting a great river-valley. During the height of the Glacial epoch, these large animals would probably retire into this Mediterranean land and into North Africa, making annual migrations northwards during the summer. But as the connecting land sank and became narrower and narrower, the migrating herds would diminish, and at last cease altogether; and when the glacial cold had passed away would be altogether prevented from returning to their former haunts.

MIOCENE PERIOD.

We now come to a period which was wonderfully rich in all forms of life, and of which the geological record is exceptionally complete. Various lacustrine, estuarine, and other deposits in Europe, North India, and North America, have furnished such a

vast number of remains of extinct mammalia, as to solve many zoological problems, and to throw great light on the early distribution and centres of dispersal of various groups of animals. In order to show the bearing of these remains on our special subject, we will first give an account of the extinct fauna of Greece, of the Upper Miocene period; since this, being nearest to Africa and Asia, best exhibits the relations of the old European fauna to those countries. We shall then pass to the Miocene fauna of France and Central Europe; and conclude with the remarkable Siwalik and other Indian extinct faunas, which throw an additional light on the early history of the animal life of the great old-world continents.

Extinct Animals of Greece.

These are from the Upper Miocene deposits at Pikermi, near Athens, and were collected by M. Gaudry a few years ago. They comprise ten living and eighteen extinct genera of mammalia, with a few birds and reptiles.

Primates. These are represented by Mesopithecus, a genus believed to be intermediate between the two Indian genera of monkeys, Semnopithecus and Macacus.

Carnivora.-These were abundant. Of Felis there were four species, ranging from the size of a cat to that of a jaguar, a large hyana, and a large weasel (Mustela). Besides these there were the huge Machairodus, larger than any existing lion or tiger, and with enormously developed canine teeth; Hyænictis and Lycana, extinct forms of Hyænidæ ; Thalassictis-Ictitherium, an extinct genus of Viverridæ but with resemblances to the hyænas, represented by three species, some of which were larger than any existing Viverrida; Promephytis, an extinct form of Mustelidæ, having resemblances to the European marten, to the otters, and to the S. African Zorilla; and lastly, Simocyon, an extraordinary carnivore of the size of a small panther, but having the canines of a cat, the molars of a dog, and the jaws shaped like those of a bear.

Ungulata.-These are numerous and very interesting. The Equidæ are represented by the three-toed Hipparion, which con

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