274 On new Neotropical Mammah. 



Skull showing a general resemblance to that of 0. hceops in 

 its thin texture, rounded and unridged brain-case, small face, 

 and narrow interorbital region. Nasals narrow, evenly 

 tapering backward; supraorbital edges square but not ridged. 

 Palatal foramina short and narrow. Molars small and 

 delicate. 



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

 lector) : — 



Head and body 92 millim. ; tail 117; hind foot (s. u.) 26; 

 ear 16. 



Skull : greatest length 26 ; basilar length 19*4 ; greatest 

 breadth 14; nasals 9*2x3; interorbital breadth 4'3 ; brain- 

 case 13 X 12 ; palate length from henselion 10*5; diastema 7 ; 

 palatal foramina 4x2; npper molar series 3'6. 



Ilab. Mirador, 20 miles E. of Banos, Oriente of Ecuador. 

 Altitude 1500 m. 



Ti/pe. Male. B.M. no. 99. 9. 9. 34. Original number 

 237. Collected 8th February, 1899, by Mr. Perry O. Simons. 

 Five specimens. 



Despite its general resemblance to members of other groups, 

 this species is probably most nearly related to 0. bieops and 

 its allies, but is readily distinguishable by its smaller size, 

 longer feet, much smaller teeth, and less woolly fur. 



Zygodontomys hrevicauda tohagi^ subsp, n. 



Closely allied in size and all other essential characters to 

 Z. h. typi'cus, but of a more dirty brownish hue, the face and 

 fore-quarters especially browner, and without the rufous tone 

 vhich characterizes the Trinidad form. On the rump alone 

 does the colour attain to nearly the reddish tone which is 

 spread equally over the whole of the head and back in typicus. 

 Under surface as in typicus, dull soiled buffy, witliout line of 

 demarcation. 



Dimensions of the type (measured in the flesh) : — 



Head and body 146 millim. ; tail 100 ; hind foot (s. u.) 30; 

 ear 18. 



Skull: greatest length 35; greatest breadth 19; length of 

 upper molar series 4 "6. 



Bab. Island of Tobago, W. Indies. Type from Richmond. 



Ty^ye. Male. B.M. no. 97. 6. 7. 47. Collected 1st March, 

 1897, by Dr. Percy Kendall. Three specimens examined. 



This is evidently a darkened insular race of the Trinidad 

 Z. hrevicauda, of which the British Museum possesses six 

 skins, obtained by Messrs, Caracciolo, Chapman, and Kendall. 



