. Natural history. Zoology. MAMMALS THAT GN'AW. 107. are several species from the Oriental countries, Tibet, and Abyssinia, the minute eyes are open ; there are small naked external ears, and the short tail is partially covered with hair. The other four genera, all of which are confined to Africa south of the Sahara, differ from other Myomorpha, and thereby resemble the under- mentioned Hystricomorpha, in that the angle of the lower jaw arises from the side of tlie sheath of the incisor. Of these, the great sand-mole {Bathyergus maritimiis) of the Cape, which attains a length of 10 inches, has
. Natural history. Zoology. MAMMALS THAT GN'AW. 107. are several species from the Oriental countries, Tibet, and Abyssinia, the minute eyes are open ; there are small naked external ears, and the short tail is partially covered with hair. The other four genera, all of which are confined to Africa south of the Sahara, differ from other Myomorpha, and thereby resemble the under- mentioned Hystricomorpha, in that the angle of the lower jaw arises from the side of tlie sheath of the incisor. Of these, the great sand-mole {Bathyergus maritimiis) of the Cape, which attains a length of 10 inches, has â. ,.â ^ ^ ' 1 ⢠⢠° â ^ â c ' Fig. 58.âBamboo-Eat grooved upper nicisors, a smgle pair of pre- {Bhizoviys badius). molar teeth in each jaw, no external ears. and extremely powerful claws. In tlie allied Georychus and Myoscalops the incisors are smooth; the members of the former genua usually have a single pair of premolars, and the single species of the latter three pairs of these teeth in both jaws, while the second toe of the hind-foot is the longest. In both, the first pair of premolars may be absent. The curious little naked sand-rats (Heterocephahis), of which the two species are confined to Somali- land, are degraded forms, with no premolars, either tsvo or tliree pairs of molars, an almost completely bare skin, small eyes, no external ears, a tail of moderate proportions, and a pair of large pads on the powerful fore- feet. These tiny little animals make shallow tunnels in the hot sand of the desert, throwing up at intervals small heaps resembling miniature vol- canic craters. This comparatively small family is exclusively confined to North and Central America, where it ranges from the pjlains of the Saskatchewan, iu Canada, southwards to Costa Rica, although attaining its maximum development in the Western United States and The Pocket- Mexico, and being unknown in the region east of the Gophers.â Mississippi, save tlie Gulf States. The essential charact
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Keywords: ., bookauthorly, bookcentury1800, bookdecade1890, booksubjectzoology
