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Show 90 MR. E. R. ALSTON ON THE ORDER GLIRES. [Jan. 18, the tail flattened, lancet-shaped, covered with short hairs and not tufted. No premolars. C. PEDETIN^E. One premolar above and below. Grinding-teeth rootless. Cervical vertebrae free. Metatarsals separate. Hind feet with four well-developed digits, with short broad hoof-like nails. Tail bushy throughout, not tufted. Ethiopian. Recent genus :- 5. Pedetes, Illiger, Prod. Syst. M a m m . p. 81 (1811). (Characters those of the subfamily.) Section III. Hystricomorpha. One premolar above and below (except in Ctenodactylus). Grinding- teeth rooted or rootless, not tuberculate. Frontals with no distinct postorbital processes (except in Chatomys). Infraorbital opening large, subtriangular, or oval. Zygomatic arch proportionally stout; malar not advancing far forward (except in Cteno-dactylince and Chinchillida), and not supported below by a continuation of the maxillary zygomatic process. Incisive foramina small; foramina in base of skull proportionally large; an interpterygoid fissure. Mandible with its angular portion springing from the outer side of the bony covering of the lower incisor, triangular, usually pointed behind ; coronoid process small, and condyle low. Clavicles perfect or imperfect. Fibula persistent as a distinct bone throughout life. Upper lip rarely cleft. Muffle clad with fine hairs. Nostrils pointed above, sigmoid or linear. Ears usually emarginate behind. Tail hairy, subnaked, or scaly. Family I. OCTODONTID^E. Grinding-teeth with external and internal enamel-folds. Malar with an inferior angle ; incisive foramina usually long, extending into the maxillaries; clavicles perfect. Both hind and fore feet usually with five digits, rarely with four ; claws curved. Teats placed high on the flanks. Tail clad with short hairs or with scales. Three subfamilies:- A. CTENODACTYLIN^E. Grinding-teeth semirooted. Malar extending to the lachrymal (as in the last family) in a flattened perpendicular plate. Hind feet with the claws of the two inner digits covered by comb-like series of bristles. Ethiopian. Recent genera:- 1. Ctenodactylus, Gray, Spicilegia Zoologica, p. 10 . . (1830). Ears very small, with no antitragus. Tail rudimentary. Interparietal and auditory bullae large ; coronoid process reduced to a ridge. No premolars. Molars with single external and internal enamel-folds. 2. Pectinator, Blyth, J. A. S. B. xxiv. p. 294 (1855). Ears with a small antitragus. Tail half as long as the body, bushy. Interparietal smaller, auditory bullae larger, and palate more contracted than in Ctenodactylus. Premolars present, but very small. Third upper molar with two external folds. |