1876.] MR. E. R. ALSTON ON THE ORDER GLIRES. 81 



C. Platacanthomyin.e, Molars f, divided into transverse 

 laminae. Intraorbital opening typical ; incisive foramina and audi- 

 tory bullse small. Form myoxine ; fur mixed with flattened spines ; 

 tail densely haired. Indian. Recent genus : — 



3. Platacanthomys, Blyth, Proc. As. Soc. Bengal, xxviii. p. 289 



(1859). 

 (Characters those of the subfamily.) 



I). Gerbillin.e. Incisors narrow ; molars divided into transverse 

 laminee. Infraorbital opening typical ; pterygoid fossaj short ; audi- 

 tory bullae usually large. Hind limbs elongated ; tail long, hairy. 

 Palsearctic, Indian, and Ethiopian. Recent genera : — 



4. Gerbillus, Desmarest, Nouv. Diet. d'Hist. Nat, xxiv. p. 22 



(1804). 

 torm murine; muzzle pointed; ears moderate, sparsely haired ; tail 

 long, hairy, slightly tufted. Skull with occipital region broad; audi- 

 tory bullae large. Incisors grooved or plain. First molar with three 

 laminae, the second with two, the third with one only. 



.5. Mystromys, "Wagner, Wiegm. Arch. 1841, p. 132 . . (1841). 



Ears large and broad ; tail moderately long, truncated, not tufted. 

 Auditory bullae smaller. Incisors plain. First molar with three 

 laminae, the second and third with two each ; these are alternated, 

 and the last is very small. 



6. Otomys, F. Cuvier, Dents des Mamm. p. 168 .... (1825). 

 Ears large, hairy ; tail moderate, clad with scales and short hairs, 



not tufted. Nasal profile more arched than in Gerbillus. Incisors 

 grooved. Molars with their laminae completely separated and united 

 by cement ; the third the longest, with from three to seven laminae. 



7. JDasymys, Peters, Monatsb. Akad. Berlin, 1875, p. 12 (1875). 

 Ears moderate, hairy ; fur somewhat coarse ; tail moderate, scaly, 



and sparsely haired. Skull intermediate between Gerbillus and Mus. 

 Lower branch of maxillary zygomatic process produced forward in a 

 hook-shape. Incisors plain. Front molars the longest ; the posterior 

 lamina of the first and the anterior laminae of the second and third 

 upper molars large and complicated. 



E. Phl(eomyin^. Incisors broad ; molars divided into transverse 

 laminae. Infraorbital opening typical. Claws large. Indian. Re- 

 cent genera : — 



8. PMoeomys, Waterhouse, P. Z. S. 1839, p. 108 ... . (1839). 



Muzzle blunt ; lip imperfectly cleft ; ears moderate, hairy exter- 

 nally ; tail moderately long, densely haired. Skull ovate; frontals 

 not contracted, with a rudimentary postorbital process at their junc- 

 tion with the squamosals ; auditory bullae very small. Incisors very 

 broad. First upper molar with three laminae ; second and third with 

 two ; first lower with four, second with three, and third with two 

 laminae. 



Proc. Zool. Soc— 1876, No. VI. 6 



