54 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



young, taken in March. The coast specimens were all collected by Mr. 

 Peterson, as follows : Gallegos River, 2 specimens, May 23 ; Halliday 

 Ranch, i specimen, June 24; Coy Inlet, 5 specimens, August 29-31, 

 and November 3-9; Cape Fairweather, 8 specimens, July 11-13. Of 

 the interior specimens, 1 1 were collected on the upper Rio Chico, by 

 Mr. Peterson, January 31 to February 8 and March i ; 13 are from 

 Basalt Canons, the type locality, collected by Mr. Colburn, April 4-29 ; 

 and 8 (mostly quite young) from Swan Lake, collected by Mr. Colburn, 

 March 12-21. 



Only about one third of the specimens, or perhaps less, can be consid- 

 ered as fully adult ; the others range from one fourth to one half grown, 

 and the remainder from one half grown to nearly full-sized young adults. 

 The younger specimens are darker, grayer, and less fulvous than the adults. 

 The old adults are quite strongly fulvous on the sides as compared with 

 the middle-aged and young adults, as shown by both the upper Rio Chico 

 specimens and the coast series. No. 84216, an old male, "Upper Rio 

 Chico, near Cordilleras, Feb. 3, 1897," is the palest and most fulvous 

 example of all, but seems to be merely an unusually light colored and 

 very fulvous extreme of the series and not specifically different. 



This species has externally the appearance of a small-eared Phyllotis. 

 Its nearest known ally appears to be E. typus [elegans Waterhouse), from 

 which it differs in having much smaller ears and shorter tail, the foot and 

 body being nearly as in E. typns. 



The type of E. elegans was collected by Darwin at Bahia Blanca and is 

 much changed in color by exposure for a long time as a mounted speci- 

 men. Two other specimens in fair condition from Chubut, eastern Pata- 

 gonia, identified as E. elegans by Mr. Thomas, very closely resemble in 

 color the series of E. morgani, but differ from them strikingly in their 

 much larger ears and much longer tails. There are no flesh measure- 

 ments, but the vertebrae still remain in the tail and the skins are fairly well 



made up. 



Eligmodontia gracilipes (Waterhouse). 



Mus gracilipes Waterhouse, P. Z. S., 1837 (November 21, 1837), ^9 

 (Bahia Blanca); Zool. Voy. Beagle, Mamm., II, 1839, 45, pi. xi, 

 animal, pi. xxiv, fig. 4, skull, teeth and under side of tarsus. 



Eligmodontia gracilipes Trouessart, Cat. Mam., ii, 1897, 532. — Thomas, 

 P. Z. S., 1898, 211, Chubut, East Patagonia. 



