70 



]Sr01lTH AMEEICAN FAUKA. 



[No. 36. 



parallel to axis of skull; subsidiary enamel loops in upper molars well 

 developed, reaching outer border of tooth. 



Measurements. — Type: Total lengthy 176; tail vertebrae, 119; hind 

 foot, 19. Skull: (See table, p. 81). 



Remarks. — This species differs widely in cranial characters from the 

 other members of the chrysopsis group. Indeed, its skull somewhat 

 resembles that of R. megalotis saturatus (which occupies the low 

 country around the base of the Cofre de Perote), especially in the 

 widely spreading zygomata and m the shape and size of the audital 

 bullse. It differs from saturatus, however, in having a much broader 

 and flatter braincase, longer and slenderer rostrum, buffy mstead of 

 white underparts, and in dental characters. 



Specimen exo^mined. — One, the type. 



REITHRODONTOMYS MEXICANUS GROUP. 



REITHRODONTOMYS MEXICANUS MEXICANUS (De Saussure). 

 Saussure Harvest Mouse. 



(PI. Ill, fig. 4; PI. VI, fig. 4; PI. VII, figs. 4, 9, 10, 11.) 



Reithrodon mexicanus De Saussure, Rev. Mag. Zool., 2d ser,, XII, 1860, p. 109. 

 Ochetodon mexicanus Coues, Proc. Acad. Nat. Sci. Phila., 1874, p. 186, 

 Reithrodontomys costaricensis jalapx Merriam, Proc. Wash. Acad. Sci., Ill, 1901, 



p. 552 (Jalapa, Vera Cruz). 

 Reithrodontomys cherriei jalap se Miller, Bull. 79, U. S. Nat. Mus., 1912, p. 130. 



Type ZocaZ%.— Mountains of Vera Cruz, Mexico. 

 Distribution. — From Jalapa, Vera Cruz, south to Chiapas and 

 Guatemala. 



Characters. — Size rather large (about like R. f. toltecus) ; tail long, 

 concolor; color uniform tawny above, white below; hind feet, ears, 

 and tail dark; skull short, broad, and flat. 



Color. — Upperparts varying from tawny to pinkish cinnamon, spar- 

 ingly darkened on the back with blackish hairs; general tone of back 

 varying from cinnamon-brown to Pr out's brown; an indistinct black- 

 ish ring around eye; tail nearly unicolor, fuscous or clove-brown to 

 fuscous-black, in some specimens slightly paler beneath; upper sur- 

 faces of both fore and hind feet dark hair-brown; toes usually buffy 

 or grayish white; ears fuscous or fuscous-black; sides of nose, upper 

 lips, and underparts white. 



STcuU. — Short and relatively broad, with very short, broad rostrum 

 and short nasals; braincase squarish, rather flat, depressed poste- 

 riorly; zygomata slender, contracted anteriorly; nasals ending behind 

 rather squarely, on a line with ends of premaxillae or slightly anterior 

 to them; outer wall of anteorbital foramen narrow; interpterygoid 

 fossa broad; palatal foramina short, ending at or slightly in front of 

 plane of first molars; audital bullae small. 



