187(3] MR. E. R. ALSTON ON THE GENUS DASYPROCTA. 351 



Dasyprocta aguti, Desmarest, Mamra. p. 358 ; F. Cuvier et 

 Geoffroy, Maram. iii. 3 mc liv. ; Waterhouse, Mamm. ii. p. 3/6 ; 

 Wagner, Suppl. Schreb. Saugeth. iv. p. 42. 



Fur ringed with black and yellow ; rump bright yellow or orange, 

 the long hairs pale yellow at their base, and only obscurely ringed 

 near the tip. Length about 20 inches. 



Guiana, N. Brazil, E. Peru. 



The range*of the Yellow-rumped Agouti is particularly difficult to 

 make out, as its specific name has been applied to almost every 

 member of the genus. It extends, however, from British Guiana, 

 where Schomburgk* says it is extremely common, through North 

 Brazil, where Natterer collected specimens near the junction of the 

 Madeira and Amazons, to Eastern Peru. In the latter country Von 

 Tschudi says that it inhabits the plains, and does not go up into the 

 mountains like D. fuliginosa. 



9. D. PRYMNOLOPHA. 



Dasyprocta prymnolopha, Wagler, Isis, 1831, p. 619 (descr. 

 orig.) ; Wagner, Suppl. Schreb. Saugeth. iv. p. 46 ; Waterhouse, 

 Mamm. ii. p. 380. 



Fur ringed with black and yellow ; nuchal crest and a longitudinal 

 band on the rump black, sides of the rump rich golden orange or 

 rufous ; the long black hair uniform in colour, or light yellow at the 

 base. Length about 20 inches ; hind foot 3*75. 



Hub. Guiana. 



Of the distribution of this most beautiful species I have been 

 unable to learn any thing beyond the fact of its being a native of 

 Guiana. It is probably a more northern race than the last, and may 

 extend into Venezuela. Many examples are now living in the Society's 

 Gardens. 



10. D. ACOUCHY. 



Cavia acouchy, Erxleben, Syst. Reg. An. p. 354 (1777, descr. 

 orig.). 



Dasyprocta acouchy, Desmarest, Mamm. ii. p. 358 ; Wagner, 

 Suppl. Schreb. Saugeth. iv. p. 48 ; Waterhouse, Mamm. ii. p. 391. 



Fur ringed with dark brown and rufous, upper parts darker, lower 

 parts and a spot behind each ear bright rufous or yellow. Tail pro- 

 duced, slender, slightly haired. Length about 14 inches, tail 2 

 inches, hind foot 3 inches. 



Hab. Guiana, N. Brazil. 



This little species, easily distinguished from all the rest by its 

 having a complete tail, instead of merely a tuberculous rudiment, is 

 abundant in Guiana and North Brazil; but I have been unable to 

 find any proof of the often repeated assertion that it is also met with 

 in some of the West-Indian Islands. Probably it has been confused 

 with D. cristata. 



Of the remaining described species, D. croconota, Wagler (Isis 



* Eei9en in Brit. Guiana, iii. p. 779. 



