new South- American Rodents. 505 



forward projection of the anterior zygoma- root, otherwise not 

 found in (Ecomys. 



The type specimen has been presented by Mr. McConnell 

 to the Museum with a further consignment of mammals from 

 the River Supinaam, whence came the collection of which I 

 gave a list iu a previous number of the ' Annals.' Several 

 additional species are now included, of which Myoprocta 

 acouchy, Coendou prehensilis, Peramys hretficaiidatus, and 

 Ateles paniscus are particularly welome accessions to the 

 Museum collections. 



(Ecomys nitedulus, sp. n. 



A small species allied to (E. rosilla and paricola. 



Colour above quite of the same rich greyish tawny as in 

 (E. rosilla, the rump similarly more tawny than the fore back. 

 Under surface white, sharply defined laterally, the hairs 

 white to the roots. Ears brown. Hands and fe.it dull buffy. 

 Tail uniformly brown above and below. 



Skull as in (E. rosilla t the tooth-row shorter than in 

 (E. paricola. 



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



Head and body 118 mm. ; tail \~1~) ; hind foot 23. 



Skull: greatest length 29 ; basilar length 223 ; breadth 

 of brain-case 13*3; palatilar length 11*8; palatal foramina 5*2; 

 upper molar series 3*7. 



Hab. Demerara, Type from the Lower Essequibo, 13 miles 

 from mouth. 



Type. Adult female. B.M. no. 6. 4. 8. 31. Collected 

 29th March, 1906, by S. B. Warren, and presented by 

 Oldfield Thomas. Three other specimens from the same 

 region presented by F. V. McConnell, Esq. 



This species is quite like the Orinoco (E. rosilla above, 

 but the under surface is without the marked oehraceous wash 

 characteristic of that animal. (Ej. paricola, which also has 

 a white belly, is duller in tone above, has black ears, and a 

 longer tooth-row. 



Dasyprocta vaviegata yungarum, subsp. n. 



General colour above more tawny brown than in true 

 variegata, the yellow rings on the hairs replaced by " tawny " 

 on the back, becoming laterally more " tawny oehraceous." 

 Under surface more yellowish, the whole breadth of the chest 

 and the middle line of belly for a breadth of about an inch 

 brilliant " orange-oehraceous/' the hairs greyish at their 



Ann. <!• Mag. N. Hist. Ser. 8. Vol. vi. 31 



