80 



NORTH AMERICAN FAUNA. 



[No. 36. 



REITHRODONTOMYS MICRODON MICRODON Merriam. 

 Small-toothed Harvest Mouse. 

 (PL III, fig. 9; PL VI, fig. 9.) 

 Reithrodontomys microdon Merriam, Proc. Wash. Acad. Sci., Ill, 1901, p. 548. 

 Type locality. — Todos Santos, Guatemala. 

 Distribution. — Highlands of Guatemala; limits unknown. 

 Characters. — Closely similar in color to R. t tenuirostris, but very 

 much smaller. 



Color. — Adults: Upperparts tawny, brighter on the sides next to 

 the belly, darkened on back and head with black, where the tone 

 becomes hazel; blackish ring around eye; underparts light pinkish 

 cinnamon; ears and tail fuscous, the latter slightly paler beneath; 

 hind feet dark hair-brown edged with whitish; toes white; fore feet 

 buffy white with a patch of dusky. Suhadults: Upperparts browner 

 (about Front's brown) and less mixed with tawny; imderparts white. 



SlcuTL. — Similar in general shape to that of R. t. tenuirostrisj but 

 very much smaller; braincase moderately inflated, narrowed and 

 depressed posteriorly; zygomata slender, decidedly contracted ante- 

 riorly; rostrum narrow; palatal foramina ending on plane of front 

 molars; interpterygoid fossa very broad; bullae rather large and 

 inflated; outer wall of anteorbital foramen very narrow. 



Measurements. — Type (9 ad.): Total length, 185; tail vertebrae; 

 113; hind foot, 21. Topotype subadult): 180; 112; 21. SkuU: 

 (See table, p. 81). 



Remarlcs. — This little species is in every way a miniature of the large 

 lenuirostrls , which Hves in the same region. 



Specimens examined. — ^Total number, 3, from the following locali- 

 ties: 



Guatemala: Todos Santos, 2; Volcan Santa Maria 1. 



REITHRODONTOMYS MICRODON ALBILABRIS Merriam. 

 White-lipped Harvest Mouse. 

 Reithrodontomys microdon albilahris MerriBm, Proc. Wash. Acad. Sci., Ill, 1901, p. 549. 



Type locality. — Cerro San Fehpe, Oaxaca, Mexico (altitude, 10,000 

 feet). 



Distribution. — Known only from the type locaHty. 



Characters. — Similar to microdon, but paler; underparts white; 

 closely similar in color to R. mexicanus goldmani. 



Color. — Upperparts pinkish cinnamon, darkened on dorsal area with 

 black, where the tone becomes snuff-brown; blackish ring around eye; 

 ears, tail, and hind feet fuscous, the last edged with whitish; toes 

 whitish; fore feet buffy, with a dusky patch; underparts white. 



SlcuU. — Very similar to that of microdon; braincase slightly broader 

 and more inflated; interpterygoid fossa narrower; bullae slightly 

 smaller; nasals ending on a line with premaxiUae; zygomata decidedly 



