468 BULLETIN 56, UNITED 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 OP NEOTOMA FOUND ON THE MEXICAN BOUNDARY. 



</. Pelage of adult, gray. 



b. Color alatish gray, dark. Length, 390 mm.; tail vertebra', ISO: hind foot, -40; ear, 25; 



skull, 48 l>v 25 Neotoma micropua ( |>. 470). 



bb. Color smoke grav, pallid. Length, oil) mm.: (ail vertebrae, 12">: hind foot, 36; ear, 



22; skull, 43 by 24 Neotoma nuicropus canesa ns (p. 471). 



aa. Adult pelage fulvous or ochraceous, noi gray. 



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

 premaxillarv hones ending evenly behind. 

 d. Size large. Length, 360 mm.; tail vertebras, 160; hind foot, 37; ear, 25; 



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



</</. Size small. Length, 350 mm.; tail vertebrae, 175; hind foot, 35; ear, 20; 

 skull. II by 21. Color paler and ochraceous. 

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



bullae normal Neotoma mexicana (p. 191). 



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



bullae peculiar Neotoma mix ten no bvllata (p. 491 ). 



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

 nasal hones ending in advance of the premaxillaries posteriorly. 



/. Tail not bicolor; hind feet dusky Neotoma fuscipes macrotis (p. 188 



ff. Tail bicolor; hind feet all white (except the heel in .V. afttrateri)- 



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

 much broader anteriorly than posteriorly ; f rentals abruptly expanded 

 behind the interorbital constriction. 

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



Neotoma ca mutator (p. 472). 

 hit. Nasal hones without an anterior spatulate enlargement; hind foot 



with the heel plumbeous Neotoma floridana atftvateri (p. 469). 



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

 nearly equal breadth throughout; frontals never abruptly expanded 

 behind the interorbital construction, but gradually increasing in 

 width from before backward. 

 i. Audita! bullae enormously inflated; pelage silky; length, 300; tail 

 vertebrae, 125; hind foot, 3(1; ear, 27. Neotoma desertorum (p. 487). 

 ii. Audital bullae moderately inflated; pelage coarser; size larger, but 

 ears smaller. 

 j. Coloration dark: skull broad. 



l\ Color above, dark olivaceous-gray, lined with blackish 



Neotoma intermedia (p. 4S4). 

 /,/,-. Color above, dark ochraceous-gray. Neotoma atbigvla (p. 476). 

 }}. Coloration pallid: skull narrow. 



"The subgenus Teonoma was revived by Meiriam in 1894 and characterized as follows: 

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

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

 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 borderof interparietal, 

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

 or open. 



