of the Palearctic region, from the Sahara to Mongolia as far as Lake Baikal. Auchenia (4 species), comprehending the Llamas and Alpacas, is equally characteristic of the mountains and deserts of the southern part of South America. Two species entirely domesticated inhabit the Peruvian and Bolivian Andes; and two others are found in a wild state, the vicuna in the Andes of Peru and Chili (Plate XVI. vol. ii. p. 40), and the guanaco over the plains of Patagonia and Tierra del Fuego.

Extinct Camelida.-No fossil remains of camels have been found in Europe, but one occurs in the deposits of the Siwalik Hills, usually classed as Upper Miocene, but which some naturalists think are more likely of Older Pliocene age. Merycotherium, teeth of which have been found in the Siberian drift, is supposed to belong to this family.

In North America, where no representative of the family now exists, the camel-tribe were once abundant. In the Post-pliocene deposits of California an Auchenia has been found, and in those of Kansas one of the extinct genus Procamelus. In the Pliocene period, this genus, which was closely allied to the living camels, abounded, six or seven species having been described from Nebraska and Texas, together with an allied form Homocamelus. In the Miocene period different genera appear,-Pabrotherium, and Protomeryx,-while a Procamelus has been found in deposits of this age in Virginia.

In South America a species of Auchenia has been found in the caves of Brazil, and others in the Pliocene deposits of the pampas, together with two extinct genera, Palæolama and Camelotherium.

We thus find the ancestors of the Camelidæ in a region where they do not now exist, but which is situated so that the now widely separated living forms could easily have been derived from it. This case offers a remarkable example of the light thrown by paleontology on the distribution of living animals; and it is a warning against the too common practice of assuming the direct land connection of remote continents, in order to explain similar instances of discontinuous distribution to that of the present family.

FAMILY 49.-TRAGULIDÆ. (2 Genera, 6 Species.)

The Tragulidæ are a group of small, hornless, deer-like animals, with tusks in the upper jaw, and having some structural affinities with the camels. The musk-deer was formerly classed in this family, which it resembles externally; but a minute examination of its structure by M. Milne-Edwards, has shown it to be more nearly allied to the true deer. The Chevrotains, or mouse-deer, Tragulus (5 species), range over all India to the foot of the Himalayas and Ceylon, and through Assam, Malacca, and Cambodja, to Sumatra, Borneo, and Java (Plate VIII., vol. i. p. 337). Hyomoschus (1 species), is found in West Africa.

Extinct Tragulida.-A species of Hyomoschus is said to have been found in the Miocene of the South of France, as well as three extinct genera, Dremotherium (also found in Greece), with Lophiomeryx from the Upper Miocene, said to be allied to Tragulus; and Amphitragulus from the Lower Miocene, of more remote affinities, and sometimes placed among the Deer. There seems to be no doubt, however, that this family existed in Europe in Miocene times; and thus another case of discontinuous distribution is satisfactorily accounted for.

3.

FAMILY 50.-CERVIDA. (8 Genera, 52 Species.)

The Cervidæ, or deer tribe, are an extensive group of animals equally adapted for inhabiting forests or open plains, the Arctic

regions or the Tropics. They range in fact over the whole of the great continents of the globe, with the one striking exception of Africa, where they are only found on the shores of the Mediterranean which form part of the Palearctic region. The following is the distribution of the genera.

Alces (1 species), the elk or moose, ranges all over Northern Europe and Asia, as far south as East Prussia, the Caucasus, and North China; and over Arctic America to Maine on the East, and British Columbia on the west. The American species may however be distinct, although very closely allied to that of Europe. Tarandus'(1 species), the reindeer, has a similar range to the last, but keeps farther north in Europe, inhabiting Greenland and Spitzbergen; and in America extends farther south, to New Brunswick and the north shore of Lake Superior. There are several varieties or species of this animal confined to special districts, but they are not yet well determined. Cervus (40 species), the true deer, have been sub-divided into numerous subgenera characteristic of separate districts. They range over the whole area of the family, except that they do not go beyond 57° N. in America and a little farther in Europe and Asia. In South America they extend over Patagonia and even to Tierra del Fuego. They are found in the north of Africa, and over the whole of the Oriental region, and beyond it as far as the Moluccas and Timor, where however they have probably been introduced by man at an early period. Dama (1 species), the fallow deer, is a native of the shores of the Mediterranean, from Spain and Barbary to Syria. Capreolus (2 species), the roe-deer, inhabits all Temperate and South Europe to Syria, with a distinct species in N. China. Cervulus (4 species), the muntjacs, are found in all the forest districts of the Oriental region, from India and Ceylon to China as far north as Ningpo and Formosa, also southward to the Philippines, Borneo, and Java. Moschus (1 species) the musk-deer, inhabits Central Asia from the Amoor and Pekin, to the Himalayas and the Siamese mountains above 8000 ft. elevation. This is usually classed as a distinct family, but M. Milne-Edwards remarks, that it differs in no important points of organisation from the rest of the Cervidae. Hydropotes Rangi..

(1 species) inhabits China from the Yang-tse Kiang northwards. This new genus has recently been discovered by Mr. Swinhoe, who says its nearest affinities are with Moschus. Other new forms are Lophotragus, and Elaphodus, both inhabiting North China; the former is hornless, the latter has very small horns about an inch long.

Extinct Deer.-Numerous extinct species of the genus Cervus are found fossil in many parts of Europe, and in all formations between the Post-pliocene and the Upper Miocene. The Elk and Reindeer are also found in caves and Post-pliocene deposits, the latter as far south as the South of France. Extinct genera only, occur in the Upper Miocene in various parts of Europe:Micromeryx, Palæomeryx, and Dicrocercus have been described; with others referred doubtfully to Moschus, and an allied genus Amphimoschus.

In N. America, remains of this family are very scarce, a Cervus allied to the existing wapiti deer, being found in Post-pliocene deposits, and an extinct genus, Leptomeryx, in the Upper Miocene of Dakota and Oregon. Another extinct genus, Merycodus, from the Pliocene of Oregon, is said to be allied to camels and deer.

In South America, several species of Cervus have been found in the Brazilian caves, and in the Pliocene deposits of La Plata.

It thus appears, that there are not yet sufficient materials for determining the origin and migrations of the Cervidae. There can be little doubt that they are an Old World group, and a comparatively recent development; and that some time during the Miocene period they passed to North America, and subsequently to the Southern continent. They do not however appear to have developed much in North America, owing perhaps to their finding the country already amply stocked with numerous forms of indigenous Ungulates.

FAMILY 51.-CAMELOPARDALIDE. (1 Genus, 1 Species.)

The Camelopardalidæ, or giraffes, now consist of but a single species which ranges over all the open country of the Ethiopian region, and is therefore almost absent from West Africa, which is more especially a forest district. During the Middle Tertiary period, however, these animals had a wider range, over Southern Europe and Western India as far as the slopes of the Himalayas.

Extinct Species.-Species of Camelopardalis have been found in Greece, the Siwalik Hills, and Perim Island at the entrance to the Red Sea; and an extinct genus, Helladotherium, more bulky but not so tall as the giraffe, ranged from the south of France to Greece and North-west India.

FAMILY 52.-BOVIDE. (34 Genera, 149 Species.)

This large and important family, includes all the animals commonly known as oxen, buffaloes, antelopes, sheep, and goats, which have been classed by many naturalists in at least three, and sometimes four or five, distinct families. Zoologically, they