Mammals from Ceard, N.E. Brazil. 501 



6. Rhipidomys cearanus, sp. n. 



? . 50. Sena de Ibiapaba. 



Very like the Guianan R. niiela, Thos., agreeing with it 

 in size, the general dull fawn-colour, and white belly, but 

 the hands are wholly brown above, and the feet are also 

 completely brown, except a narrow light line along the 

 hallucal border and on the tips of the toes. Tail less heavily 

 haired than in nitela, scarcely tufted at all. 



Skull with the mesopterygoid fossa narrow, parallel-sided, 

 not broadened anteriorly, penetrating the palate as far as the 

 level of the front of m 3 ; parapterygoid fossae flat, their outer 

 border not raised, and their floor not excavated as is the case 

 in R. nitela. Molar series rather longer than in nitela. 



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



Head and body 101 mm.; tail 128, hind foot 26; 

 eas 18. 



Skull : greatest length 29'5 ; basilar length 22*5; nasals 

 9*6 ; interorbital breadtli 4*8; breadth of brain-case 13 6; 

 palalilar length 11*4; palatal foramina 6'3x2'7; upper 

 molar series 4'9. 



Type. Young adult female. Original number 50. Col- 

 lected 8th February, 1910. 



This Rhipidomys is readily distinguished from R. nitela 

 by its darker feet and the different structure of its posterior 

 narial region. No other species seems to be nearly related 

 to it. 



11 Taken in a house." — E. S. 



7. Oryzomys subflavus, Wagn. 



<?. 4 ; ?. 21. Ipu. 



<J. 45, 48, 51 j ?. 39,52, 57, 76, 77, 79. Serra de 

 Ibiapaba. 



" llato verm el I io."—E. S. 



8. Oryzomys sp. 



? . 19. Ipu. 

 O. eliurus group. 



9. Zyyodontomys lasiurus, Lund. 



<J. 15. Ipu. 



S . 25, 29, 32, 35, 36, 38 ; ? . 27, 28, 33, 34, 37. Serra 

 de Ibiapaba. 



" Native name ' Pishuna/ Very common in the maize- 

 fields."—^. S. 



