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Show 80 MR. E. R. ALSTON ON THE ORDER GLIRES. [Jan. 18, end. Stomach simple. Angular portion of the mandible perforate. Grinding-teeth smaller; their crowns concave, with few and faintly marked folds. 4. Graphiurus, F. Cuvier & Geoffroy, Mammiferes, 60me livr. (1845). Tail short, cylindrical, ending in a pencil. Mandible not perforate. Grinding-teeth very small; their crowns flat, with hardly a trace of enamel-folds. Family II. L O P H I O M Y I D ^ E. No premolars; molars rooted and tuberculate. Skull as in the typical Muridee, but with the temporal fossae completely arched over by thin plates developed from the temporal ridge and the malar, articulated with one another ; surface of skull granulated. Clavicles imperfect. Caecum small. Form thickset. Hair long, forming a crest along the back and tail. Ethiopian. Recent genus : - Lophiomys, A. Milne-Edwards, LTnstitut, xxxv. p. 46 . (1867). (Characters those of the family.) Family III. MURIDAE. Lower incisors compressed ; no premolars (except in Sminthina); molars rooted or rootless, tuberculate or with angular enamel-folds. Frontals contracted. Infraorbital opening in typical forms high, perpendicular, wide above and narrowed below, with the lower root of the maxillary zygomatic process more or less flattened into a perpendicular plate; very rarely the opening is either large and oval or small and subtriangular. Malar short and slender, generally reduced to a splint between the maxillary and squamosal processes. External characters very variable. Pollex rudimentary, but often with a small nail. Tail generally subnaked and scaly, rarely densely haired. Cosmopolitan. Ten subfamilies*:- (a Molars rooted.) A. SMINTHINA. Premolars \, molars f-. Infraorbital opening subtriangular, widest below. Incisive foramina long. Palaearctic. Recent genus :- 1. Sminthus, Keyserling & Blasius, Wirbelth. Europ. p. 38 (1840). (Characters those of the subfamily.) B. HYDROMYIN^E. Molars §, divided into transverse lobes. Infraorbital opening crescentic, scarcely narrowed below. Incisive foramina and auditory bullae very small. Hind feet partly webbed. Australasian. Recent genus :- 2. Hydromys, Geoffroy, Ann. du Mus. vi. p. 81 .... (1805). (Characters those of the subfamily.) * Supra, p. 69. |