N. Australia; Cricetomys (1 sp.) Tropical Africa; Saccostomus (2 sp.) Mozambique; Cricetus (9 sp.) Palæarctic region and Egypt; Cricetulus (1 sp., Milne-Edwards, 1870) Pekin; Pseudomys (1 sp.) Australia; Hapalotis (13 sp.) Australia; Phlæomys (1 sp.) Philippines; Platacanthomys (1 sp., Blyth, 1865) Malabar; Dendromys (2 sp.) S. Africa; Nesomys (1 sp. Peters, 1870) Madagascar; Steatomys (2 sp.) N. and S. Africa; Pelomys (1 sp.) Mozambique; Reithrodon (9 sp.) N. America, Lat. 29° to Mexico, and south to Tierra del Fuego; Acodon (1 sp.) Peru; Myxomys (1 sp.) Guatemala; Hesperomys (90 sp.) North and South America; Holochilus (4 sp.) South America; Oxymycterus (4 sp.) Brazil and La Plata ; Neotoma (6 sp.) U.S., East coast to California; Sigmodon (2 sp.) Southern United States; Drymomys (1 sp.) Peru; Neotomys (2 sp.), S. America; Otomys (6 sp.) S. and E. Africa; Meriones = Gerbillus (20-30 sp.) Egypt, Central Asia, India, Africa; Rhombomys (6 sp.) S. E. Europe, N. Africa, Central Asia; Malacothrix (2 sp.) South Africa; Mystromys (1 sp.) South Africa; Psammomys (1 sp.) Egypt; Spalacomys (1 sp.) India; Sminthus (1-3 sp.) East Europe, Tartary, Siberia; Hydromys (5 sp.) Australia and Tasmania; Hypogeomys (1 sp., Grandidier, 1870) Madagascar; Brachytarsomys (1 sp., Günther, 1874) Madagascar; Fiber (2 sp.) N. America to Mexico; Arvicola (50 sp.) Europe to Asia Minor, North Asia, Himalayas, Temp. N. America; Cuniculus (1 sp.) N. E. Europe, Siberia, Greenland, Arctic America; Myodes (4 sp.) Europe, Siberia, Arctic America, and Northern United States; Myospalax Siphneus (2 sp.) Altai Mountains and N. China1; Lophiomys (1 sp.) S. Arabia, and N. E. Africa; Echiothrix (1 sp.) Australia.

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Extinct Murida.-Species of Mus, Cricetus, Arvicola, and Myodes, occur in the Post-Pliocene deposits of Europe; Arvicola, Meriones, and the extinct genus Cricetodon, with some others, in the Miocene.

1

In North America, Fiber, Arvicola, and Neotoma, occur in caves;

Myospalax has hitherto formed part of the next family, Spalacidæ ; but a recent examination of its anatomy by M. Milne-Edwards shows that it belongs to the Muridæ, and comes near Arvicola.

an extinct genus, Eumys, in the Upper Miocene of Dakota, and another, Mysops, in the Eocene of Wyoming.

In South America Mus, or more probably Hesperomys, is abundant in Brazilian caverns, and Oxymycterus in the Pliocene of La Plata; while Arvicola is said to have occurred both in the Pliocene and Eocene deposits of the same country.

FAMILY 56.-SPALACIDE. (7 Genera, 17 Species.)

The Spalacidæ, or mole-rats, have a straggling distribution over the Old World continents. They are found over nearly the whole of Africa, but only in the South-east of Europe, and West of Temperate Asia, but appearing again in North India, Malacca, and South China. Ellobius (1 sp.), is found in South Russia and South-west Siberia; Spalax (1 sp.), Southern Russia, West Asia, Hungary, Moldavia, and Greece (Plate II., vol. i. p. 218); Rhizomys (6 sp.), Abyssinia, North India, Malacca, South China; Heterocephalus (1 sp.), Abyssinia; Bathyerges (= Orycterus 1 sp.), South Africa; Georychus (6 sp.), South, Central, and East Africa; Heliophobus (1 sp.), Mozambique.

FAMILY 57.-DIPODIDÆ. (3 Genera, 22 Species.)

The Jerboas, or jumping mice, are especially characteristic of the regions about the eastern extremity of the Mediterranean, being found in South Russia, the Caspian district, Arabia, Egypt, VOL. II.-16

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and Abyssinia; but they also extend over a large part of Africa, and eastward to India; while isolated forms occur in North America, and the Cape of Good Hope. Dipus Gerbillus (20 sp.), inhabits North and Central Africa, South-East Europe, and across Temperate Asia to North China, also Affghanistan, India, and Ceylon; Pedetes (1 sp.), South Africa to Mozambique and Angola; Jaculus Meriones (1 sp.), North America, from Nova Scotia and Canada, south to Pennsylvania and west to California and British Columbia (Plate XX., vol. ii. p. 135).

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Extinct Dipodidae.-Dipus occurs fossil in the Miocene of the Alps; and an extinct genus, Issiodromys, said to be allied to Pedetes of the Cape of Good Hope, is from the Pliocene formations of Auvergne in France.

FAMILY 58.-MYOXIDE. (1 Genus, 12 Species.)

GENERAL DISTRIBUTION.

NEARCTIC

PALEARCTIC ETHIOPIAN

ORIENTAL AUSTRALIAN

NEOTROPICAL

SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS.

The Dormice (Myoxus), are small rodents found over all the temperate parts of the Palearctic region, from Britain to Japan; and also over most parts of Africa to the Cape, but wanting in India. Some of the African species have been separated under the name of Graphidurus, while those of Europe and Asia form the sub-genera Glis, Muscardinus, and Eliomys.

Extinct Myoxida.-Myoxus ranges from the Post-pliocene of the Maltese caverns to the Miocene of Switzerland and the Upper Eocene of France; and an extinct genus Brachymys is found in the Miocene of Central Europe.

FAMILY 59-SACCOMYIDE. (6 Genera, 33 Species.)

GENERAL DISTRIBUTION.

ORIENTAL AUSTRALIAN

NEOTROPICAL NEARCTIC PALEARCTIC ETHIOPIAN
SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS.

The Saccomyidæ, or pouched rats, are almost wholly confined to our second Nearctic sub-region, comprising the Rocky Mountains and the elevated plains of Central North America. A few species range from this district as far as Hudson's Bay on the north, to South Carolina on the east, and to California on the west, while one genus, doubtfully placed here, goes south as far as Honduras and Trinidad. The group must therefore be considered to be pre-eminently characteristic of the Nearctic region.

The genera are,-Dipodomys (5 sp.), North Mexico, California, the east slope of the Rocky Mountains to the Columbia River, and one species in South Carolina; Perognathus (6 sp.), North Mexico, California, east slope of the Rocky Mountains to British Columbia; Thomomys (2 sp.), Upper Missouri, and Upper Columbia Rivers to Hudson's Bay; Geomys (5 sp.), North Mexico, and east slope of Rocky Mountains to Nebraska (Plate XIX., vol. ii. p. 129); Saccomys (1 sp.), North America, locality unknown; Heteromys (6 sp.), Mexico, Honduras, and Trinidad. Geomys and Thomomys constitute a separate family Geomyidæ, of Professor Carus; but I follow Professor Lilljeborg, who has made a special study of the Order, in keeping them with this family.

In the Post-Pliocene deposits of Illinois and Nebraska, remains of an existing species of Geomys have been found.

FAMILY 60.-CASTORIDE. (1 Genus, 2 Species.)

The Beavers, forming the genus Castor, consist of two species, the American (Castor canadensis) ranging over the whole of North America from Labrador to North Mexico; while the European (Castor fiber) appears to be confined to the temperate regions of Europe and Asia, from France to the River Amoor, over which extensive region it doubtless roamed in prehistoric times, although now becoming rare in many districts.

Extinct Castoride.-Extinct species of Castor range back from the Post-pliocene to the Upper Miocene in Europe, and to the Newer Pliocene in North America. Extinct genera in Europe are, Trogontherium, Post-Pliocene and Pliocene; Chalicomys, Older Pliocene; and Steneofiber, Upper Miocene. In North America Castoroides is Post-Pliocene, and Palæocastor, Upper Miocene. The family thus first appears on the same geological horizon in both Europe and North America.

FAMILY 61. SCIURIDÆ.—(8 Genera, 180-200 Species.)

GENERAL DISTRIBUTION.

NEOTROPICAL NEARCTIC

PALEARCTIC ETHIOPIAN

ORIENTAL

AUSTRALIAN

SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS. SUB-REGIONS.

The Squirrel family, comprehending also the marmots and prairie-dogs, are very widely spread over the earth. They are especially abundant in the Nearctic, Palæarctic, and Oriental regions, and rather less frequent in the Ethiopian and Neotropical, in which last region they do not extend south of Paraguay. They are absent from the West Indian islands, Madagascar, and Australia, only occurring in Celebes which doubtfully belongs to the Australian region. The genera are as follows: