52 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



furnished. There appears to be but one large tubercle on the under side 

 of the tarsus, and this, which is situated near the base of the toes, is 

 thickly covered with silvery-white hairs. The tail is long, pale brown 

 above, and pale flesh-colour beneath ; above, it is furnished with minute 

 brown hairs, and on the under side with white hairs. The ears are rather 

 large, of a pale flesh-colour tolerably well clothed with hairs, which are 

 of a pale yellow colour on the inner side, and white on the outer side — 

 excepting on the fore part, where they are brown. A small tuft of white 

 hairs springs from the base of the ear posteriorly. The hairs of the mous- 

 taches are moderate ; black at the base, and grayish at the apex. 



Inches. Lines. [mm] 



" Length from nose to root of tail 3 7 91 



Length of tail 3 9 44.8 



Length from nose to ear i o 25.4 



Length of tarsus o 10 21 



Length of ear o 6 12.7 



"Habitat, Bahia Blanca (September)." — Waterhouse, Zool. Voy. 

 Beagle, /. c. 



Based on a single specimen, collected by Darwin, who says: "Whilst 

 bivouacking one night on shore, amongst some sand hillocks, this mouse, 

 with its tail singed, leapt out of a bush which was placed on the fire. Its 

 hind legs appeared long in proportion to the front, and it did not appear 

 to be very active in endeavouring to make its escape." 



Mr. Durnford, in his field notes on this species, published by Mr. 

 Thomas (/. c.) says: "Not uncommon among bushes, into which it climbs 

 readily. Comes out in the evening to feed. Like the long-tailed Rat 

 \EHgiiwdo7itia gnseoflava\ this species is most numerous in the summer, 

 though during the winter a few may be found. It does not enter the 

 house like its large relative, but is extremely numerous in the thick scrub 

 and brushwood in the neighborhood of the Colony, and universally dis- 

 tributed. It makes a small oval nest of fine grass and any soft material, 

 which it places in the centre of a thick bush. It never burrows in the 

 ground, but is extremely numerous among the thorn-bushes." 



F. Cuvier's name typiis for this species appears to have unquestionable 

 priority ONtxelegansoi Waterhouse, the signature date of Cuvier's paper on 

 Eligmodontia being March, 1837, while the signature of the Proceedings 

 of the Zoological Society containing Mr. Waterhouse's paper was not 



