280 Mr. O. Thomas on 



Type B.M. no. 98. 3. 16. 5; original number 1740. 

 Killed May 20, 1897. 



Jt is with great doubt that I place this remarkable mouse 

 in the genus Phyllotis^ as its short tail and hairy feet give it 

 a very different appearance to that of Ph. Darwini, the typical 

 species of that group. Ph. boliviensis, however, seems so to 

 connect the two forms that, until further material is obtained, 

 !Mr. Garlepp's mouse may be provisionally referred to 

 Phyllotis. 



Chinchillula, gen. nov. 



Form approximately that of the short-tailed species of 

 Phyllotis. Ears very large. Fur excessively long and 

 soft. Palms and soles naked, except just under the heel, 

 with 5-6 pads ; pollex with a rather elongated nail. 



Skull very much as in Phyllotis, but the molar teeth enor- 

 mously enlarged and very high-crowned, their greatest 

 breadth equal to the space between the anterior pair. In 

 pattern they are simpler than in Phyllotis, the posterior 

 lamina of in.^ simply transverse and not tending to be con- 

 stricted into two loops ; 7n." and m.^ without anterior supple- 

 mentary cusps and the general pattern simpler, posterior 

 lamina of vi.^ much narrower than the anterior. Lower 

 molars similarly modified ; the posterior supplementary hooks 

 absent, and the last molar, instead of being more or less 

 sigmoid, consisting of two simple laminiB connected mesially, 

 the posterior much smaller than the anterior. 



Chinchillula sahamcPj sp. n. 



Size about as in Phyllotis Jhrwini, but general form ap- 

 pearing stouter, mainly on account of the length of the fur. 

 Pelage excessively long, soft and silky, very like that of a 

 Ciiinchilla both in colour and texture, the underfur about 18 

 or 19 millim. long on the back, and mixed with a few longer 

 hairs, which attain to upwards of 25 millim. General colour 

 above cineieous grey, washed with blackish; the hairs of the 

 back slaty tor four- lift lis their length, then pale greyish white, 

 and finally tipped with black. The projecting ends of the 

 longer hairs are black, except on the rump, where they are 

 v;hite. Eyes faintly black-ringed. Ears large, rounded, 

 their visible surfaces, when folded, black ; a small white 

 patch at the base of their outer margin. Outer side of hij)9 

 with a whitish projection ruiniing up from the belly-colour 

 into that of the back, succeeded behind by a blacker area on 

 the back of the hams, and this again succeeded by a white 



