Goldman — Five New Mammals from Mexico and Arizona. 137 



tawny on the head, with a narrow stripe of paler fur along median line 

 of back ; underparts between zinc orange and tawny. Female: Upper- 

 parts near buckthorn brown ; underparts pale yellow ocher. 



Skull. — Similar in form to those of N. I. leporinus and N. I. mastivus, 

 but smaller ; maxillary toothrow shorter, the teeth relatively broader, 

 or more extended transversely. 



Measurements. — Type (dry skin) : Forearm, 83.2; tibia, 37; foot, 33.5. 

 An adult male topotype : 83.9; 37.1; 32.9. Two adult female topotypes : 

 82, 85.8; .35.5, 36.8; 32, 31. Skull (type):* Greatest length, 28.5 (26.4, 

 26.2); condylo-incisive length, 25.2 (24.7, 24.3); zygomatic breadth, 

 19.8 (18.6, 18.7); interorbital breadth, 7.4(7.1, 6.8); length of maxillary 

 toothrow, 10.7 (10.4, 10.1). 



Remarks. — Specimens from various localities in South America and the 

 West Indies have been used for comparison, of which those from Trinidad 

 are assumed to represent typical N. I. leporimis,^ while a pair from Mono 

 Island have been taken to represent N. I. mastivus, in the absence of 

 material from the type locality, the neighboring island of Saint Croix. 

 While the exact status of N. I. leporinus and N. I. mastivus seems not 

 entirely clear. South American, and West Indian specimens from as far 

 west as Jamaica differ from the Mexican series, especially in larger size. 

 The males in forms of N. leporinus are larger than the females. Occa- 

 sional females, in the Mexican form, at least, may, however, have fore- 

 arms about as long as males of greater general dimensions. 



Specimens examined. — Nine, all from the type locality. 



* Measurements of two adult female topotypes in parentheses. 



f Type locality, Surinam (see Thomas. Proc. Zool. Soc. London, p. 131, March, 1911). 



