, r )72 Mr. O. Thomas on new 



buffy, the bases of the hairs slaty. Ear with the proectote 

 little darkened. Chin white. Hands and feet white. Tail 

 long, brown above, creamy white below. 



Skull a miniature of that of 0. stolzmanni, the anteorbital 

 plate of ' zygoma well developed, projecting forwards. 

 Bruin-case not specially enlarged. Interorbital space narrow, 

 the narrow part long and evenly curved, not specially di- 

 vergent posteriorly ; supraorbital edges sharply square. 



Dimensions of the type (measured in the flesh) : — 



Head and body 80 mm. ; tail 100; hind foot 21 ; ear 15. 



Skull: greatest length 22*5 ; condylo-incisive length 1 9*4 ; 

 zygomatic breadth 11*4; nasals 7*8; interorbital breadth 3 ; 

 brain-case breadth 10*5 ; palatilar length S - 8 ; palatal fora- 

 mina 4"1 ; upper molar series 3. 



Ilab. Coast desert of N.W. Peru. Type from Eten ; sea- 

 level. 



Type. Adult male. B.M. no. 0. 3. 1. 60. Original number 

 574. Collected 14th September, 1899, by P. O. Simons. 

 Presented by Oldfield Thomas. 



This is a small pale desert species of the widely spread 

 group with well-developed anteorbital plate to the zygoma 

 and normal-sized brain-case. In these respects it agrees 

 with the much larger O. stolzmanni, and differs widely from 

 O. minulus, dri/as, and their allies. Perhaps its nearest ally 

 is O. mnnchiquensis, Allen, from W. Colombia, but that is a 

 mountain form, and is not nearly so pale as G. arena! is. 



FJigmodontia morgani pampamm, subsp. n. 



Essential characters of the Patagonian E. morgani, but 

 paler throughout. General colour above pale mouse-grey, 

 with but little buffy suffusion ; an inconspicuous buffy line 

 edging the ventral colour on the lower flanks. Under surface 

 pure white, the hairs white to the bases except just along the 

 sides of the belly, where they have grey bases; in true 

 morgani all the hairs of the under surface (except just on the 

 chin and interrainia) have broad dark slaty bases. 



Skull as in true morgani. 



Dimensions of the type (measured in flesh) : — 



Head and body 7'5 mm. ; tail 80; hind foot 20 ; ear 17. 



Skull : greatest length 23*4 ; condylo-incisive length 20*2 ; 

 upper molar series 3'6. 



Hah. Southern Argentine Pampas. Type from Peru 

 Station, F.C.P. ; about 200 kilometres N.W. of Bahia 

 Blanca. 



Type. Adult female. B.M. no. 13.11. 1. fi. Original 

 number 8. Collected 2nd August, 1913, and presented by 

 F. II. F. Parkes, Esq. 



