r 93-] Allen, Mammals from New Mexico and Durango. 6oi 



They are mostly young . adults, but include 2 middle-aged 

 adults and i very old female. If these specimens are rightly 

 referred to S. minimus, they show that minimus may, when 

 old, attain nearly the size of 5. fulviventer, from which, how- 

 ever, it differs widely in coloration. The old female and the 

 two middle-aged specimens (male and femate) measure, re-. 

 spectively, as follows: Total length, ? 269, $ 238, ? 228; 

 tail vertebras, 114, 95, 98; hind foot, without claws, 29, 25, 

 24 (with claws about 3 mm. more); ear from notch, 18, 18, 19. 

 The Durango series averages rather grayer, with darker 

 (less brownish apically) underfur, than several Arizona speci- 

 mens available for comparison, and may prove subspecifically 

 separable. 



13. Sigmodon baileyi, sp. nov. 



Type, No. 20993, ? ad., La Cienega de las Vacas (altitude 8500 feet), 

 northwestern Durango, March 27; J. H. Batty. 



Pelage rather soft. General color of upper parts gray brown, nearly 

 without fulvous suffusion, the sides faintly tinged with pale buff, the 

 long hairs of back and sides tipped with soiled white, mixed abundantly 

 with black-tipped hairs; underparts white, the basal portion of the 

 hairs ashy plumbeous; sides of nose conspicuously ochraceous buff; 

 region at base of tail suffused with cinnamon buff; ears rather dark 

 gray on both surfaces; soft woolly hair at posterior base of ears pale 

 buff; feet pale buffy gray; tail well-haired, bicolor, blackish brown 

 above and all around for apical fourth, pale buffy gray below. 



Total length (type), 198; tail, about 90 (slightly imperfect); hind 

 foot (without claws), 25; ear (from notch), 18. Skull, total length, 

 31.5; basal length of Hensel, 27.3; nasals, 12.5; zygomatic breadth, 

 18.3; mast oid breadth, 13.3; alveolar length of upper molar series, 5.6. 



Represented by 5 specimens : the type, from La Cienega de las 

 Vacas; 3 young adults from Rancho Santuario, Feb. 26 and March i; 

 and i young adult from Arroyo de Bucy, May 30. The type is an 

 adult female that appears to have raised young ; the teeth are consider- 

 ably worn and the skull has well-developed ridges. 



Sigmodon baileyi is a very gray, conspicuously yellow-nosed 

 form, apparently closely resembling Sigmodon hispidus major 

 in general coloration, but very much smaller at least one 

 half smaller in general bulk. It belongs to the same group as 

 Sigmodon hispidus arizoncs Mearns and 5. h. major Bailey, 

 which appear to be both specifically separable from true 



