Descriptions of Nine New Mammals. 169 



large and handsome wood rat "is abundant everywhere on the 

 lower parts of the wooded hill slopes and adjacent dry ground 

 covered with mesquite and other seed-bearing trees. It is strictly 

 nocturnal, and usually lives in holes or burrows at the foot of a 

 tree or under some convenient shelter, from which its pathway 

 or trail, neatly cleared of brush, leaves, and twigs, leads away. 

 It lives also in ledges of loose rock, and in a few such places 

 small collections of sticks, shells of land crabs, and other Neotoma 

 bric-a-brac were found. These were rare, however. Where the 

 animals are common these trails intersect one another and form 

 a network on the brush and tree-covered slopes. Sometimes 

 their runways reach down on the low wooded flats close to the 

 coast, but they are not common in such places." 



Neotoma tenuicauda pp. nov. 



Type No. tjjjj:^ cT ad. U. S. National Museum (Department of Agri- 

 culture collection). From north slope of the Sierra Nevada de Colima, 

 Jalisco, Mexico (altitude 3,()50 meters, or 12,000 feet), April 13, 1892. 

 Collected by E. W. Nelson. (Original number, 244(5.) 



Measurements (in millimeters, taken in flesh by collector). 

 Total length, 340; tail vertebrae, 160; hind foot, 81. 



General Characters. Size smallest of the known species, being 

 slightly smaller even than N. mexicana; tail slender and sparsely 

 haired, bicolor; ears rather small, sparsely haired; fore feet 

 soiled white ; hind feet whitish, clouded with dusky. 



Color. Upper parts dark brown, more or less suffused with 

 yellowish fulvous, particularly on the neck and shoulders, pass- 

 ing into dark fulvous on the flanks and hips ; under parts soiled 

 white (the plumbeous basal color showing through), with a 

 salmon patch on the inner side of each axilla; tail bicolor, 

 dusky above and whitish below ; fore feet and ankles soiled 

 white; hind feet whitish, strongly clouded with dusky prox- 

 imally (the dusky fading out in passing over the metatarsals) ; 

 toes pure white. 



Cranial and Dental Characters. Nasals rather short, not reach- 

 ing plane of lachrymals, ascending rami of pivinaxilla? ending 

 on plane of lachrymals ; audital bullse rather large for a Neotoma; 

 molar series narrow, with sharply angular prisms ; first upper 

 molar with an internal lateral closed triangle ; lower molars with 



