468 BULLETIN 56, IJNTTED STATES NATIONAL MUSEUM. 



the vicinity of the Mexican Line belong to the subgenus Teonoma, "' 

 proposed, in 1843, by J. E. Gray for the group of bushy-tailed wood 

 rats. 



KEY TO THE SPECIES AND SUBSPECIES OF NEOTOMA FOUND ON THE MEXICAN BOUNDARY. 



a. Pelage of adult, gray. 



h. Color slatish gray, dark. Length, 390 mm.; tail vertebra?, 180; hind foot, 40; ear, 25; 



skull, 48 by 25 Neotoma micropns (p. 470). 



hh. Color smoke gray, pallid. Length, 310 mm.; tail vertebrae, 125; hind foot, 36; ear, 



22 ; skull, 43 by 24 Neotoma micropus canescens (p. 471). 



aa. Adult pelage fulvous or ochraceous, not gray. 



c. Anterior loop of first upper molar completely divided by a deep sulcus ; nasal and 

 premaxillary bones ending evenly behind. 

 (/. Size large. Length, 360 mm.; tail vertebra^, 160; hind foot, 37; ear, 25; 



skull, 47 by 24. Color dark fulvous Neotoma pinctorum (p. 490). 



(/(/. Size small. Length, 3.50 nmi.; tail vertebra, 175; hind foot, 35; ear, 20; 

 skull, 44 by 21. Color paler and ochraceous. 

 e. Color pale, ochraceous, slightly darkened by black-tipped hairs; audita! 



bullae normal Neotoma mexicana (p. 491). 



ee. Color darker, clay-color, much darkened by black-tipped hairs; audita! 



bullae peculiar Neotoma mexicana hullata (p. 491). 



cc. Anterior loop of first upper molar without, or incompletely, divided by, a sulcus; 

 nasal bones ending in advance of the premaxillaries posteriorly. 



/. Tail not bicolor; hind feet dusky Neotoma fnscipes macrotis (p. 488). 



ff. Tail bicolor; hind feet all white (except the heel in N. attwateri). 



g. Skull of adult more than 45 mm. in length; upper molar series very 

 much broader anteriorly than posteriorly ; f rontals abruptly expanded 

 behind the interorbital constriction. 

 h. Nasal bones enlarged and spatulate anteriorly; hind foot all white 



Neotoma cumulator (p. 472). 

 Ml. Nasal bones without an anterior spatulate enlargement; hind foot 



with the heel plumbeous Neotoma flondana attwateri (p.' 469). 



gg. Skull of adult 45 mm. or less in length; upper molar series of more 

 nearly equal breadth throughout; f rontals never abruptly expanded 

 behind the interorbital construction, Init gradually increasing in 

 width from before backward. 

 i. Audital bulla? enormously inflated; pelage silky; length, 300; tail 

 vertebrae, 125; hind foot, 30; ear, 27. Neotoma desertorum (p. 487). 

 a. Audital bulla? moderately inflated; pelage coarser; size larger, but 

 ears smaller, 

 y. Coloration dark; skull broad. 



Jc. Color above, dark olivaceous-gray, lined with blackish 



Neotoma intermedia (p. 484). 

 U. Color above, dark ochraceous-gray.iVeotoma albigula (p. 476). 

 jj. Coloration pallid; skull narrow. 



nThe subgenus Teonoma was revived by Merriam in 1894 and characterized as follows: 

 Tail very large, bushy, and somewhat distichous, like a squirrel's; hind feet very large. 

 Rostrum much elongated, measuring more than one-third the total length of cranumi; 

 posterior roots of zygomata widely spreading; sagittal area long, narrow, and sharply angu- 

 lar, its broadest part far back, on or nearly on plane of anterior border of interparietal, 

 whence the sides bend abruptly back to interparietal shields; phenopalatine vacuities closed 

 or open. 



