ALLEN : MAMMALIA : MURIDyG. 53 



delivered to the Society by the printer till Nov. 21, 1837. (G^ Sclater, 

 P. Z. S., 1893, 437-) 



Eligmodontia morgani Allen. 



(Plates IX, Fig. i, Skull ; X, Figs. 2 and 3, Teeth.) 



Eligmodontia niorga m AWtn, Bull. Am. Mus. Nat. Hist, XIV, 409, Nov. 

 30, 1 90 1. Basaltic Canons, 50 miles southeast of Lake Buenos 

 Aires, Patagonia (" Arroyo Else" on the labels and in the original 

 description). 



Pelage very full, long and soft. Above dull ochraceous gray, finely 

 lined with black, sides paler and more buffy, passing into a well-defined 

 pale yellowish lateral line, extending from the sides of the nose to the 

 base of the tail ; lower parts pure white, the fur plumbeous at base, the 

 apical half white ; ears medium, dusky brown externally, pale buffy gray 

 internally; tail nearly as long as head and body, sharply bicolor, dark 

 brown above, grayish white below, well haired and slightly penicillate ; 

 fore and hind feet above grayish white, well covered with short hairs ; 

 soles and palms flesh color, sparsely haired, the flesh-colored skin barely 

 showing through the hairs. 



Measurements. — Total length (of type), 165 mm. ; head and body, 85 ; 

 tail, 80 ; hind foot, 23; ear (from dry skin), 13. 



Different specimens, apparently adult or nearly so, vary greatly in 

 measurements, as shown by the following : Nine topotypes, all males but 

 one, collected and measured by Mr. Colburn : Total length, 153 (145- 

 165) ; tail vertebrae, 72.5 (65-80) ; hind foot, 22.5 (22-23). Five (2 males 

 and 3 females) from the upper Rio Chico, collected and measured by Mr. 

 Peterson : Total length, 165 (148-180) ; tail vertebras, 77 (70-84) ; hind 

 foot, 23 (21-24). Seven specimens from Cape Fairweather and vicinity 

 (all males but one), collected and measured by Mr. Peterson : Total 

 length, 150 (144-170) ; tail vertebrae, 69.4 (66-77) I ^^"^^ foot, 22.5 (22-24). 



Skull much as in E. typus, but rather smaller, and with the same 

 character of dentition. Total length (type), 24 ; basilar length, 17.5 ; zygo- 

 matic breadth, 1 2 ; mastoid breadth, 1 1 ; interorbital breadth, 4 ; length of 

 nasals, 10 ; palate, 5 ; palatal foramina, 5x2; interparietal, 1 1 x 2.5 ; upper 

 toothrow, 4; lower jaw, 12; height at condyle, 5.3; lower toothrow, 4. 



This species is represented by 48 specimens, of which 17 are from the 

 coast and 31 from the interior, and among the latter are several quite 



