The genus Tarniops is a group allied to the Palm Squirrels but distinguished by the dorsal stripes being black in colour and i or 3 in number ; they are found in Assam, Manipur, Tenasserim, Yunnan and Siam. Nanosciurus, the Oriental Pigmy Squirrels, are very similar to the West African Pigmy Squirrels, but have larger molars and 5 cheek-teeth instead of 4-; seven different forms have been described from Malacca, Sumatra, Borneo, and the Philippines. N. samaricus, from Samar, has the following dimensions :—head and body 88 mm. ; tail 69 mm.; hindfoot 25 mm. A group of small squirrels from the Guianas has been placed in the genus Sciurillus (p. mammae 6) ; in
general dimensions rather larger than Nanosciurus.
The Chipmunks, Eutamias and Tamias, are small, striped squirrels which may be regarded as a connecting link between the true squirrels and the Marmots, Prairie-dogs, Spermophiles, and Antelope Squirrels. The group is found in North America and Eastern Asia.
The Prairie-dogs (Cynomys) are entirely con fined to the New World, and are distinguished by their very short tails, rudimentary ears, and large teeth; postorbital processes well developed, and palate contracted posteriorly. About 9 forms are recognised, divided into two subgenera, the typical one, and Leu cocrossuromys. The genus Citellus, including the Spermophiles, Pouched Marmots, American Ground Squirrels or Sousliks, is found throughout a large area of the Northern Hemisphere, from Hungary eastward through Asia and North America to the central United States. Like the Prairie-dogs the members of this genus are strictly terrestrial, with a short flattened tail. General size medium. (head and body 195-220 mm.; tail 6o-75 mm.). Ammospermoph ilus (Antelope-squirrels), Callospermophilus and Otospermoph ilus are closely allied genera inhabiting the New World. The Marmots (Marmota) have a similar distribution, being found from the Alps eastward through Asia and North America. These animals are more badger-like in form than Sciurine, the body being massive and the tail short and bushy; unlike the two preceding genera cheek-pouches are either absent or but little developed. Dimensions of M. marmota (Alps) :—head and body 55o mm. ; tail 15o mm.
(III.) Petauristidae.—Flying Squirrels of the Northern Hem isphere, extending from Scandinavia and northern Russia eastward throughout the greater part of Asia to the southern United States; in general appearance squirrel-like, but having the fore and hind limbs connected by a parachute-like fold of skin, supported by a cartilaginous spur arising from the wrist. Eleven genera are known, the most important of which are the following :—Eupe taunts, a large flying squirrel (head and body 515-610 mm. ; tail 38o-48o mm. ; hindfoot 86 mm.) with hypsodont or tall-crowned cheek-teeth, in this respect differing from all the other Petauris tidae. E. cinereus is dark grey in colour and has been recorded only from Astor and Gilgit. Another genus of large Asiatic Flying
Squirrels is Petaurista, which includes some very brightly coloured forms ; teeth normal, brachyodont. These squirrels are found over a large part of Asia, extending from the Indian Peninsula and Ceylon, through Nepal, Bengal and Burma into China, Siam, the Malay Peninsula and Islands as far east as Japan. Among the smaller flying squirrels the following may be noted : Petromyscus, with brachyodont teeth, and small ears; found in Malacca and Borneo; and Sciuropterus, with the molar ridges well developed, found in Scandinavia, Russia and eastward to Japan.
or American Sewellels, distinguished from the Sciuridae by the absence of postorbital processes and the cheek-teeth being rootless; premolars f.. The Sewellels are me dium-sized terrestrial rodents with short tails and very small eyes.
or Beavers, found both in the Old and the New World, confined to the forested portions of the Northern Hemisphere south to the Mediterranean region and southern United States. The skull lacks the postorbital process and the cheek-teeth are rootless, premolars 1; size of body large, tail flat and broad, hindfeet webbed, and habits aquatic. Two species are recognized, C. fiber from Scandinavia and a few of the larger European rivers ; and C. canadensis from North America.
The jugal seldom extends far f or ward, the zygomatic arch being supported by the zygomatic process of the maxilla ; tibia and fibula united; postorbital processes absent, and angle of mandible usually arising as in the Sciuromorpha.
or Dormice, widely distributed over the Old World, from England to Japan ; and south as far as Cape Colony ; usually the members of this family are of small size with large rather bushy tails and large ears. There is no caecum and the pre molars are -I-. The typical genus Muscardinus, extends from Eng land into Asia Minor, and south to the Mediterranean. The Com mon British Dormouse, M. avellanarius, is the smallest member of the family. Three other genera of this family are found in Europe : (i.) Eliornys, which extends eastward into Asia Minor and south to Northern Africa; (ii.) Dyromys, which occurs in Hungary and Switzerland, spreading eastward to Central Asia through Asia Minor; and (iii.) Glis, found in Central and South ern Europe extending east to Asia Minor and south to Sardinia and Spain. The latter genus contains the Edible Dormouse, a large grey-coloured form (head and body about 17o mm.) ; easily dis tinguished from the other European species by its large size and squirrel-like appearance. In Africa the family is well represented from south of the Sahara to Cape Colony; Graphiurus ocularis being a large grey-coloured form from Cape Colony, Namaqua land and Damaraland. The other African genus is Claviglis, containing a large number of small and medium sized species.