OTOTYLOMYS. 221 



both ends; mandible with angle excavated posteriorly, a backward pro- 

 jecting point; infracondyloid notch long and deep ; coronoid process 

 minute; postcoronoid notch flat, nearly horizontal, (ex Merr., 1. c.) 



KEY TO THE SPECIES. 

 A. Ears very large; tail long as head and body, 



naked, scaly, 

 a. Above grayish or fulvous brown. PAGE 



a.' Size large; back uniform in color O. phyllotis 221 



b/ Size smaller; back varying in color 0. p. ph&us 221 



200. phyllotis (Ototylomys] , Merr., Proc. Wash. Acad. Scien., in, 



1901, p. 562. 

 TUNKAS RAT. 



Type locality. Tunkas, Yucatan, Mexico. 



Genl. Char. Similar to Tylomys in appearance; characters those 

 of the genus. 



Color. Above grayish or fulvous brown, sometimes mixed with 

 black-tipped hairs ; under parts and inner sides of legs white ; cheeks 

 and about eyes fulvous ; tail above brownish dusky, beneath yellowish ; 

 hands and feet whitish; wrists and ankles dark; ears flesh color at 

 base, rest black. 



Measurements. Total length, 303; tail, 148; hind foot, 28. 

 (ex Type.) Skull: occipito-nasal length, 39; Hensel, 31.8; zygomatic 

 width, 24.3; interorbital constriction, 5.6; length of nasals, 14; 

 palatal length, 15.6; length of upper molar series, 5.3; length of 

 mandible, angle to alveolus of incisor, 18.6. 



a. phceus (Ototylomys) , Merr., Proc. Wash. Acad. Scien., in, 1901, 



P- 563- 

 APAZOTE RAT. 



Type locality. Apazote, near Yohaltun, State of Campeche, Mexico. 



Genl. Char. Similar to O. phyllotis, but smaller; tail shorter; 

 colors darker. 



Color. Above dark grayish brown, mixed with black, hinder 

 part of dorsal region dusky; anterior part of back and sides grayish 

 brown, tinged with fulvous; arms white; legs grayish brown; hands 

 and feet white; tail dark brown above, yellow beneath; ears flesh 

 color at base, rest black. 



Measurements. Total length, 266; tail, 136; hind foot, 26.5. 

 (ex Type.) 



The Genus HOLOCHILUS introduced here by Miller and Rehn. 

 Syst. Res. N. Am. Mamm., 1902, p. 89, to follow TYLOMYS, has no 

 species north of the Isthmus of Panama, and H . piloridcs, Pallas, is 

 a native of the island of Ceylon. 



