1894.] DIDELPHYIDiE OF S.E. BRAZIL. 459 



"Winge x 2 , and Hensel 3 — it appears that, however many recognizable 

 forms of the subgenus Didelphys there may ultimately be, all the 

 Opossums obtained by myself in the Orgaos Mountains are 

 exclusively D. aurita, whether this be itself reckoned as " species " 

 or " variety." This is distinctly the animal so well represented by 

 Burrueister, plate hi. of his 'Erlauterungen.' And the determi- 

 nation becomes certain from the cranial views (Burmeister, pi. v. 

 tig. 3, pi. vi. fig. 1) and the osteological details given by Hensel 

 (tigs. 3, 6). Evidently it was not one single character, but a 

 complexity of features, which engaged Winge not to drop D. albi- 

 ventris as a remarkable and constant Campos-variety of D. marsu- 

 pialis. The same complexity of features occurs to me in regard 

 to D. aurita of the forest coast-region of Bio de Janeiro 4 ; and I 

 may now add that during a stay of more than ten years in this 

 province, in the hot and low zones, as well as in the mountains of 

 the Serra dos Orgaos, I have always met with exactly the same 

 form among the hundreds of specimens I had occasion to see. 



Some of the specimens in my collection agree exactly with 

 Burmeister's plate hi., showing the same general reddish-brown 

 colour of fur, with longer whitish or greyish piles on the whole 

 back or at least on the posterior part. Others are more or less 

 blackish, with louger piles or bristle-hairs of the same colour, the 

 points of these piles being split, as a rule, into many branches, 

 especially on the dorsal median line, and appearing dirty white. 

 No correlation with age, sex, or season could be discovered in 

 regard to the presence or absence of the whitish piles, and I made 

 exactly the same observation referred to by Hensel (p. 112). I 

 took notes about the last twelve specimens I saw : seven of them 

 had white bristle-hairs intermixed, while five were more or less 

 blackish. Of these seven specimens four were adult males, one a 

 young male, one an old female, and one a half-grown female. 

 They were collected in August 1891, April 1892, February 1893, 

 May 1893, and three in December 1893. The five blackish 

 specimens were caught in October 1S92, February, March, July, 

 and August 1893, and three of them were males (old, medium, 

 and young) ; two were females, both half-grown 5 . The face- 



1 ' Jordfundene og unlevende Pungdyr (Marsupialia) fra Lagoa Santa, Minas 

 Geraes, Brasiliens,' Kjobenhavn, 1893. 



2 Lagoa Santa. Et Bidrag til den biologiske Plantegeografi af Egnens 

 Varming,' Kjobenhavn, 1892. (Lagoa Santa Egnens Hvirveldyr.) 



3 " Beitrage zur Kenntniss der Saugethiere Siid-Brasiliens," Abhand. d. 

 Konigl. Akad. d. Wissensch. Berlin, 1892. 



4 It can be seen by Pelzeln's 'Brasilische Saugethiere' (VVien, 1883), p. 109 

 et scq., that Natterer also determined all his specimens of large Didelphys, 

 collected in the neighbourhood of Rio de Janeiro and the coast-region, :is 

 belonging to I). aurita. About six specimens collected in Sapitiba (district of 

 Rio de Janeiro) Natterer noted on the label a sign of question, but Pelzeln 

 adds the words: — " Diirfte wohl zu D. aurita zu recline u Bein ( wiilirend die 

 echte I), cancrivora dem Norden Biid-Amerikae angehort." It is to be regretted 

 that Pelzeln's work on Natterer's Brazilian Mammals is not provided with 

 good illustrations, especially of the smaller Didelphyidae and Rodents. 



' Hensel states that anion" 07 individuals of 1). OZO/TCB ho noted 11 black 



