684 CLASS xvir. 



■with molars ^— ?, the first ujiper small, with buccal pouches none, accord- 



4-4 

 ing to Douglas, with claws of fore feet very long, tail very short. 



Family XXVIII. Muriformia [Psammoryctma Wagn. in part, 



Orycterina WiEGM.) Incisors with ajiex truncated, straight. 



4 — 4 

 Molars almost always j^^ • Feet pentadactylous or tetradacty- 



lous, congruous. Ears moderate, sometimes large. 



This family contains some rodents, principally from South 

 America, which cannot well be referred to any of the other families, 

 but is not sharply defined. Under a future improved arrangement 

 of the Glires, for which the time appears not yet to have arrived, 

 and which may be much more simple than is now supposed, this 

 family will doubtless be dropped, 



3 — 3 



Ctenodactylus Gkay. Incisors white, smooth ; molars ^>_o ? 



the upper with crown oblong, emarginate externally, the lower 

 with crown narrowed on each side, oblique. Ears small. Whiskers 

 long. Feet tetradactylous ; inner toe of hind feet furnished with a 

 horny comb ; rigid, curved hairs concealing the small compressed 

 claws. Tail very short. 



Ctenodactylus Massonii Gray, Spic. Zool. Tab. lo; Tripoli; yellowish- 

 grey, resembling a lemming externally. Comp. Yaerell's elaborate de- 

 scription. Proceedings of the Zool. Soc. 1830 — 1831, pp. 48 — 50. 



4-4 

 Petromys Smith. Incisors smooth, pale yellow ; molars j — j^ , 



with crown divided into two transverse, oval lamellte, the upper 

 folded internally, the lower externally. Ears small, rounded. 

 Whiskers long, numerous. Feet pentadactylous, with pollex short; 

 claws incurved, small, compressed. Tail elongate, clothed with 

 rigid hair, longer towards the extremity. 



Sp. Petromys typicus Smith Zool. of S. Afr., Mamm. PI. ■20, Waterh. 

 Mamm. 2, PI. 17, fig. i ; of the size of a rat, red-brown, tail blackish. 



4 — 4 



Cercomys F. Cuv. Molar teeth j — j > complex. Head pro- 

 tracted in front of mouth. Ears ample, somewhat naked. Whis- 

 kers long. Fore feet tetradactylous, with thumb-wart unguiculate, 



