56 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



Mus griseoflavus^2X^x\\o\x'=^&, Zool. Voy. Beagle, Mamm., II, 1839, 62, pi. 



xxii, animal, pi. xxxiv, fig. 16, skull and teeth. 

 Hesperomys gyiseoflaviis Burmeister, Descrip. phys. Rep. Argent, III, 



1879, 219. Rio Chubut, collected by Durnford. 

 Eligmodontia griseofiava Thomas, P. Z. S., 1898, 210. Chubut, East 



Patagonia. 

 Phyllotis gyiseoflaviis Trouessart, Cat. Mamm., 1897, 534. — Lahille, Congr. 



Cien. Lat. Amen, III, 1899, 187.— Allen, Bull. Am. Mus. Nat. Hist, 



XIV, 1 90 1, 408. 

 This species is recorded from Chubut by Mr. Thomas (/. c\ and thus 

 comes within the region included in the present work. The following is 

 a transcript of Waterhouse's description in the Mammalia of the Voyage 

 of the Beagle. 



" Ears large ; tail rather shorter than the head and body taken together ; 

 tarsi slender, and moderately long ; fur long and very soft ; general tint 

 of the upper parts of head and body grayish, washed with brownish yellow ; 

 on the sides of the body a palish yellow tint prevails ; feet, chin, throat, 

 and under parts of body pure white ; tail rather sparingly clothed with 

 hairs, those on the apical portion rather long, and forming a slight pencil 

 at the tip ; on the upper side and at the tip of the tail the hairs are brown, 

 on the under side they are dirty white ; the ears are very sparingly clothed 

 w^ith minute brownish yellow hairs internally ; externally, on the fore part, 

 the hairs are rather longer and of a brown colour ; the upper incisors are 

 orange, and the lower incisors are yellow; the hairs of the moustaches 

 are long, and of a black colour ; the hairs of the back are deep gray at the 

 base, brownish at the tip, and annulated with pale brownish yellow near 

 the tip ; the longer hairs are brown ; the hairs of the belly are white extern- 

 ally, and gray at the base ; on the throat the hairs are white to the root. 



Inches. Lines. mm. 



" Length from nose to root of tail 6 8 168 



Length of tail 5 6 140 



Length from nose to ear i a\ 35-3 



Length of tarsus (claws included) i 2\ 30.8 



Length of ear o 8 16.8 



" Habitat, Northern Patagonia (August)." 



Darwin adds : " Inhabits the dry gravelly plain, bordering the Rio 

 Negro." 



Respecting the reference of this species to the genus Eligmodontia 

 instead of to Phyllotis, Mr. Thomas observes : 



