RHITHRODONTOMYS. 205 



Measurements. Total length, 183; tail vertebrae, 102; hind foot, 

 19; ear, 14. Skull: occipito-nasal length, 21; Hensel, 15; zygomatic 

 width, 10; interorbital constriction, 3; length of nasals, 7; palatal 

 length, 8; length of upper molar series, 3; length of mandible, 9.5; 

 length of lower molar series, 4. 



c. gracilis (Reithrodontomys!), Allen & Chapman, Bull. Amer. Mus. 



Nat. Hist., 1897, p. 9. 

 CHICKEN ITZA HARVEST MOUSE. 



Type locality. Chichen Itza, Yucatan, Mexico. 



Geogr. Distr. Yucatan, Mexico. 



Genl. Char. Similar to R. mexicanus, but smaller and paler. 



Color. Above yellowish brown, lined with blackish on median 

 line; sides fulvous brown; under parts white; ears brownish; tail 

 unicolor, brown; hands and feet whitish. 



Measurements. Total length, 165; tail vertebrae, 98; hind foot, 

 16; ear, 13. Skull: total length, about 20; width of braincase, 10; 

 interorbital constriction, 3 ; length of nasals, 7 ; length of upper 

 molar series, 3. (ex Type.) 



256. tenuis (Reithrodontomys!), Allen, Bull. Am. Mus. Nat. Hist., 



1899, p. 15. 

 SLENDER HARVEST MOUSE. 



Type locality. Rosario, State of Sinaloa, Mexico. 



Geogr. Distr. State of Sinaloa, Mexico; range unknown. 



Genl. Char. Similar to R. m. julvescens, but smaller. 



Color. Upper parts yellowish brown, lined with black; lateral 

 line from before the eyes and along flanks fulvous ; under parts grayish 

 white; base of hairs pale plumbeous; ears dusky, internally reddish, 

 tail grayish brown; feet whitish. 



Measurements. Total length, 152-170; tail vertebrae, 82-90; 

 hind foot, 20; ear, 15. 



257. chrysopsis (Reithrodontomys!), Merr., Proc. Biol. Soc. Wash., 



xin, 1900, p. 152. 

 MOUNT POPOCATEPETL HARVEST MOUSE. 



Type locality. Mt. Popocatepetl, Mexico. 



Geogr. Distr. State of Mexico, Mexico; range unknown. 



Genl. Char. Size large; ears large; tail very long, hairy. Skull: 

 no superorbital beads; zygoma notched by antorbital slits; bullae 

 small; rostrum narrow. 



Color. Upper parts golden yellow, mixed with black; under 

 parts white, tinged with salmon fulvous; tail above dusky, beneath 

 white; ears and ankles dusky; hands and feet white. 



