408 Mr. 0. Thomas on 



liiglilands of Peru and Bolivia, including Caylloma, Arequipa, 

 La Paz, &c. Further eastwards it probably grades into the 

 form I named wolffsohni, which has, however, a rather 

 differently shaped skull. 



Phyllotis darwini tucumanus, subsp. n. 



Proportions as in darwt'ni. Colour dark. Nasals narrow. 



Size about as in true darwini. Fur long and fine. 

 General colour dark, about as in Ph. lutescens. Under 

 surface dull soiled grey'sh buffy, less white than in most of 

 the races of duriGini. Ears not very large. Hands and feet 

 white. Tail rather longer than head and body, well haired, 

 blackish above, white below. 



Skull slightly smaller than tliat of true darwini, rather 

 larger than that of lutesceiis. Nasals comparatively narrow, 

 tapering backwards to a fine point. Interorbital region 

 narrow, its edges less sharply angular than usual. 



Dimensions of the type (measured in flesli) : — 



Head and body 107 mm.; tail ("two or three vertebrae 

 lost") 110; liind foot 24; ear 22. 



Skull : greatest length 'SI ; condylo-incisive length 29'2; 

 zygomatic breadth 15*8 ; nasals 13*5 ; interorbital breadth 4 ; 

 palatilar length 14*5; palatal foramina 7"8 ; upper molar 

 series 5*2. 



Ilab. Cunbre de Mala-mala, Sierra de Tucuman. Alt. 

 3300 m. 



Ti/pe. AduU female. B.M. no. 4.10.2.6. Original 

 number 3027. Collected 10th April, 1904, by E. Dinelli. 

 Presented by Oldtield Thomas. Two specimens. 



The skull of this animal is somewhat intermediate between 

 that of Ph. darwini and Ph. lutescens, but 1 consider it pro- 

 visionally as being more allied to the former. No species of 

 this group have been previously recorded from anywhere 

 near Tucuman. 



Phyllotis darwini vaccarum, subsp. n. 



A mountain race of Ph. darwini, with long hair and 

 yellowish rump. 



Size larger than in true darwini of the Central Chilian 

 lowlands. Fur very long; hairs of back about 15 mm. in 

 length. General colour paler than in true darwini, the upper 

 surface suffused with buffy, especially on the rump, which is 

 strong clear buffy. Face greyer. Under surface of the 

 usual dull greyish white. Hands and feet white. Tail 

 heavily haired, dark brown above, white below. 



