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, 60 me 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. Lophiomyid^e. 



No premolars ; molars rooted and tuberculate. Skull as in the 

 typical Muridce, but with the temporal fossse 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, L'Institut, xxxv. p. 46 . (1867). 

 (Characters those of the family.) 



Family III. Murid.e. 



Lower incisors compressed ; no premolars (except in Sminthince) ; 

 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 per- 

 pendicular 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. Ex- 

 ternal 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. Sminthince. Premolars \, molars f . Infraorbital opening 

 subtriangular, widest below. Incisive foramina long. Paleearctic. 

 Recent genus : — 



1. Sminthus, Keyserling & Blasius, Wirbelth. Europ. p. 38 



(1840). 

 (Characters those of the subfamily.) 



B. Hydromyin^e. Molars §, divided into transverse lobes. In- 

 fraorbital 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. fi9. 



