80 Goldman Descriptions of Five New Mammals from Mexico. 



by a rather abundant sprinkling of black-tipped hairs ; under parts nearly 

 pure white (in some specimens suffused with salmon), the plumbeous 

 basal color showing through indistinctly; axillae orange- ru fous ; ears 

 covered with short dusky hairs; tail indistinctly bicolor (occasionally 

 concolor), dusky above, paler below; fore feet yellowish white; hind 

 feet to toes irregularly clouded with dusky or pale fulvous, the toes white. 



Skull. The skull indicates close relationship to N. tennicauda, but is 

 slightly larger and the nasals are longer. Compared with N. ferruginea, 

 the skull is smaller, with narrower frontal region. 



Measurements. Type : Total length, 368 ; tail vertebrae, 180; hind foot, 



37. Average of eight adult females from the type locality : Total length, 

 344 (338-355) ; tail vertebrae, 170 (166-182) ; hind foot, 34 (33-35.5). Skull 

 of type: Greatest length, 43.3; basilar length of Hensel, 35 ; zygomatic 

 breadth, 23; length of nasals, 17.4; interorbital breadth, 5; palatal 

 length, 8.6; diastema, 11.9; upper molar series on alveolus, 8.7. 



Specimens examined. Total number, 31, all from the State of Guerrero, 

 as follows: Mountains near Chilpancingo (type locality), 16; Omilteme, 

 15. 



Remarks. Neotoma picta appears to be more closely related to N. tcnni- 

 cauda than to any other known form, but its remarkable color is alone 

 sufficient to distinguish it from that species. 



Neotoma isthmica sp. nov. 



Type from Huilotepec, 8 miles south of Tehuantepec, Oaxaca, Mexico 

 (altitude, 100 feet). Adult female, No. 73,187, U. S. National Museum, 

 Biological Survey Collection, May 5, 1895, E. W. Nelson and E. A. Gold 

 man. Original number 7843. 



Characters. Size rather large ; color orange-rufous to ferruginous ; tail 

 long, moderately stout, thinly haired and coarsely scaly ; ears medium. 

 Similar to N. ferruginea, but much brighter colored and without dusky 

 forearms and hind legs; skull narrower and heavier. In color closely 

 resembling N. picta, but larger, with stouter, more coarsely scaly tail, and 

 differing in cranial characters. 



Color. Type (in worn pelage) : Upper parts in general between orange- 

 rufous and ferruginous of Ridgway, fading to grayish fulvous on outer 

 sides of forearms and hind legs; face, top of head, and back thinly sprin 

 kled with blackish hairs ; under parts, including upper lip, lower sides of 

 face, and inner sides of fore and hind legs, soiled white; tail indistinctly 

 bicolor, brownish above, paler below ; fore feet pure white; hind feet to 

 toes clouded with dusky (in some specimens pure white), the toes white. 



Skull. Similar to that of N. ferruginea but narrower, heavier, and more 

 arched across anterior roots of zygomata. Compared with N. picta the 

 skull is larger, longer, heavier, relatively narrower, and more arched 

 across anterior roots of zygomata; frontal region flatter posteriorly; 

 braincase less smoothly rounded. 



Measurements. Type : Total length, 395; tail vertebras, 198; hind foot, 



38. Average of nine adult males and females from the type locality : 



