new Neotropical Mammals. 273 



lonf^ and slender, fifth hind toe reaching to the middle of the 

 basal phalanx of the fourth. Tail slender, naked, finely- 

 scaled, brown above, scarcely paler below. 



Skull very similar in its general shape and delicate build 

 to that of 0. gracilis, but much larger. Nasals and pre- 

 inaxillge about level posteriorly. Supraorbital edges evenly 

 divergent, finely beaded, the beading extending backward 

 nearly half across tlie parietals. Palatal foramina small and 

 narrow. Teeth of normal proportions. 



Dimensions of the type (measured in the flesh by col- 

 lector) : — 



Head and body 112 millim.; tail 118; hind foot 29; 

 ear 2 1 . 



Skull : extreme length 30'5 ; basilar length 22*8 ; greatest 

 breadtli 15; nasals, length 12; interorbital breadth 4-9; 

 jjalate lengtli from henselion 13 ; diastema 7" 8 ; palatal 

 foramina 4"0 ; length of upper molar series 4*5. 



Hab. Santa Rosa, Southern Ecuador. Altitude 10 m. 



Type. B.M. no. 0. 1. 1. 21. Original number 440. Col- 

 lected 30tli June, 1899, by Perry C). Simons. 



This species is exactly intermediate in size between the 

 large 0. laticeps and the small 0. gracilis, and may therefore 

 bo readily distinguished by size from either of them, to which 

 alone it has any resemblance in general characters. Probably 

 it is most nearly allied to 0, gracilis. 



Oryzomys balneator, sp. n. 



General appearance that of a dark-coloured member of the 

 O. longicaudatus group, but really more allied to 0. bceops. 



Size small, rather less than in 0. gracilis. Fur fairly- 

 straight, not so woolly as in 0. bceops. Colour above dark 

 greyish brown, heavily lined with black, the general effect 

 not far from the " bistre " of Ridgway. Rump* with a suffu- 

 sion of reddish fawn. Face like back. Cheeks and flanks 

 dull fawn ; outer side of hips deeper fawn. Under surface 

 dark soiled greyish, the hairs slaty grey basally, dull whitish 

 terminally ; the line of demarcation little defined. Ears 

 small, finely haired, black. Limbs coloured on outer sides 

 like back, on inner sides like belly ; upper surface of hands 

 and feet greyish brown ; hairs at base of claws white; feet 

 long and slender ; fifth hind toe reaching to the middle of the 

 basal phalanx of the fourth. Tail slender, almost naked 

 except towards the end, dark brown above, rather lighter 

 below ; extreme tip slightly pencilled, commonly (in four out 

 of five examples) white. 



Ann. & Mag. N. Hist. Ser. 7. Vol. v. 18 



