194 Mr, O. Thomas on new Callithrix, Midas, &c. 



Dimensions of tlie type (measured in tlie flesli) : — 



Head and bodj 112 mm.; tail 151; hind foot (s. u.) 25; 

 ear 15. 



Skull : greatest length 32 ; basal length 24*5 ; zygo- 

 matic breadth 17; nasals, length 10' 7 ; interorbital breadth 

 5-6; brain-case, breadth 15; palate length 12'4 ; diastema 8*2; 

 palatal foramina 6*3 X 2*4 ; length of upper molar series 4* 7. 



Ilah. Rio Verde, N.W. Ecuador. Alt. 1000 m. 



Type. Adult male. B.M. no. 1. 1. 6. 4. Collected 

 6th December, 1899. 



This EliipidoinyH appears to be the Ecuadorean represen- 

 tative of R. venezueice, but it is smaller than either that 

 species or B. latimanus, Tomes. It may also be related to 

 my R. microtis of Bogota, but has larger ears. 



Rhipidomys paricola, sp. n. 



A very small species of the R. dryas group. 



Size almost or quite the smallest of the genus. Fur 

 rather sparse, hairs of back about 6 mm. long. General 

 colour dark rufous grey, much duller than in R. dryas; sides 

 but little clearer rufous. Under surface dull creamy white, 

 not sharply defined laterally ; the hairs slaty basally, except 

 on the throat and the centre of the chest. Outer aspect of 

 limbs like body, inner whitish, the hind limbs not so white as 

 the anterior ones. Hands and feet dull buffy, the hallucal 

 edges of the metatarsals lighter. Ears of medium size, the 

 airterior part of their backs blackish, contrasting with the 

 general colour. Tail slender, uniformly blackish, not well 

 haired for this genus, the scales scarcely hidden, and the tip 

 with but a slight pencil, of which the hairs are only about 

 2\ mm. long. 



Skull very similar to that of R. dryas. 



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



Head and body 100 mm.; tail 100 ; hind foot (s. u.) 22; 

 ear 17. 



Skull : greatest length 25 ; basilar length 19'3 ; inter- 

 orbital breadth 4-7; palatine foramina 4x2T; length of 

 upper molar series 4"2. 



Ilah. Igarapd-Assu, near Para. Alt. 50 m. 



Type. Female. B.M. no. 4. 7. 4. 63. Original number 

 1872. Collected 29th April, 1904, by Alphonse Robert. 



'J his species is evidently most closely allied to tlie Ecua- 

 dorean R. dryas, but may be readily distinguished by its 

 much duller coloration. The recently described R. rosilla is 

 also a member of the same group. 



