380 Mr. 0. Thomas ou 



dark in the middle of the back ; sides clearer but still dull 

 fulvous. Under surface from chin to anus rich ochraceous 

 fulvous, the hairs slaty grey basally ; line of demarcation on 

 sides fairly sharply defined. Head like body, the middle line 

 blackish, the cheeks more fulvous. Ears rather large, dusky 

 brown. Fifth hind toe reaching to the middle of the basal 

 phalanx of the fourth ; metapodials brown above, digits 

 inconspicuously whitish ; soles quite naked. Tail long and 

 slender, practically naked, brown throughout except basally 

 below, where it is slightly lighter ; scales small, averaging 

 about 1 3 to the centimetre. 



Supraorbital edges sharply square, witii slight ridges 

 which run back to the middle of the parietals. Palatal 

 foramina not reaching back to the molars. 



Dimensions of the type (an old male, measured in the flesh 

 by collector) : — 



Head and body 147 millim. ; tail 160 ; hind foot (s. u.) 35 ; 

 ear 23. 



Skull (of a second, rather younger, male) : greatest 

 length 38; basilar length 29'2 ; greatest breadth 19'G; 

 nasals 13 X 4*5; interorbital breadth 5*6; interparietal 

 4:"3xl0'5; palate length froui henselion 16'2 ; diastema 10; 

 palatal foramina 5'6x 2*5; length of upper molar series 6-3. 



Bab. Mirador, below Baiios, on the Upper Pastasa River, 

 E. Ecuador. Altitude 1500 m. 



Type B.M. no. 99. 9. 9. 25. Collected Feb. 8, 1899, by 

 Mr. P. 0. Simons. Original number 239. Two specimens 

 obtained. 



This fine species has a certain superficial resemblance to 

 0. aureus^ Tomes, but the characters of its feet and skull 

 show it to be really more allied to some of the members of 

 the 0. laticeps or 0. gracilis group, from all of which it may 

 be readily distinguished by its peculiar coloration. 



Zygodontomys stelhe, sp. n. 



Similar to Z. hrevicauda in general appearance, but much 

 smaller, less rufous in colour, and with whiter feet. 



Fur straight, hairs of back about 10 millim. in lengtii. 

 General colour above uniform grizzled fawn, the black and 

 fawn about equally mixed ; sides rather but not cons|jicuously 

 paler. Under surface greyish, the hairs slaty basally, dull 

 whitish terminally ; no sharp line of demarcation on sides. 

 Head like back, no darker markings round eyes. Ears of 

 medium size, thinly haired, dull fawn or grey, no white spot 

 on the head behind tliem. Arms and legs fawn-grey^ upper 



