1902.] Allen, Opossums of the Genus Didelphis. 265 



as the basis of comparison, the apparent difference in size 

 practically vanishes. 



Didelphis marsupialis aurita (Wied). 



Didelphys marsupialis WIED, Beitr. zu Naturg. Bras. II, 1826, 387 



(not of Linnasus) . 



Didelphys aurita WIED, Beitr. zu Naturg. Bras. II, 1826, 393. "Villa 

 Vicoza am Flusse Peruhype." Gray phase. BURMEISTER, 

 Thiere Bras. Ill, 1854, 130, gray phase; Erlaut. zur Fauna Bras. 

 1856, 64, pi. iii, animal, pi. v, fig. 3 and pi. vi, fig. i, skull (not 

 the reference to D. azarce Temminck, etc.). PELZELN, Verh. 

 z.-b Gesell. Wien, XXXIII, Anh. 1883, 109, part; southern 

 Brazil. GOELDI, P. Z. S. 1894, 457. Serra dos Orgaos, Brazil. 

 Didelphis marsupialis aurita COPE, Am. Nat. Feb. 1889, I2 9> I 49- 



Sao Joao do Monte Negro, Rio Grande do Sul. 

 Didelphys azarcs WAGNER, Schreber's Saug. Suppl. Ill, 1843, 38 



(mainly); ibid. V, 1855, 22 3 (part). 



Didelphys cancrivora BURMEISTER, Thiere Bras. Ill, 1854, 129 = D. 

 marsupialis Wied, (non Linn). Dark phase. HENSEL, Phys. 

 Abhandl. Akad, Wiss. Berlin, 1872 (1873), 114, pi. i, figs. 2 

 and 5. Rio Grande do Sul. PELZELN, Verh. z.-b Gesell. Wien, 

 XXXIII, Anh. 1883, no (Sapitiba). WINGE, Jordfunde og 

 nulevende Pungdyr (Marsupialia) fra Lagoa Santa, etc., E. 

 Museo Lundii, II, 1892, 8, pi. i, figs. 9, 96; pi. iii, fig. 4; pi. iv, 

 fig. 10. 

 Didelphys koseritzi IHERING, Mamm. do Rio Grande do Sul, 1892, 99 



(p. 6 of separates). Black phase. 



Type locality. Villa Vifoza, Rio Peruhype, southeastern Brazil. 

 Based on a single specimen, in the gray phase. 



Geographical Distribution. Southeastern Brazil, from Bahia (?) 

 south to Rio Grande do Sul, and westward to Matto Grosso, Paraguay, 

 northern Argentina, and eastern Bolivia. 



Adult. Dichromatic, with a gray phase and a black phase. An 

 average adult in gray phase (Brit. Mus. No. 1-2-7-61, ? ad., Cruzeiro, 

 alt. 530 m., San Paulo, Brazil, A. Robert, Nov. 14, 1900) may be 

 described as follows: 



Above soiled white, strongly varied with black; long overhair white 

 to base, 80100 mm. long on lower back; underfur clear yellowish 

 white to base on middle of back, dirty yellowish brown at extreme 

 base on sides, apical third to half black, coarser, almost bristly; below 

 pelage much shorter and more woolly, brownish white basally, and 

 tipped with blackish brown, with a sprinkling of yellowish white 

 hairs ; woolly hairs at edge of pouch dark brown or blackish chestnut ; 

 an indistinct spot of clear white on middle of chest; lower throat 



