﻿THE OPOSSUMS. 219 



known. Length of head and body of male about 2^ inches ; 

 of tail i^ inch. 



Distribution. — Rio Grande do Sul. 



XXI. THREE-STRIPED OPOSSUM. DIDELPHYS AMERICANA. 



Sorex americanus^ P.L.S., Miiller, Lin. Natursyst. Suppl., vol. 



vii., p. 36 (1776). 

 Sorex braziliensis, Erxleben, Syst. Regn. Anim., vol. i., p. 127 



(1777)- 

 Didelphys fristriata, Illiger, Abhandl. Akad. Berlin, 18 11, p. 



107 (1815). 

 Didelphys trilt?teata, Lund, Blik. Brasil. Dyrev., Dansk. 



Afhand., vol. viii., p. 237 (1841). 

 Feramys tristriata, Lesson, Nouv. Tabl. Rbgne Anim., Mamm., 



p. 187 (1842). 



Didelphys americana^ Thomas, Cat Marsup. Brit. Mus., p. 363 



(1888). 



{Plate XXXV.) 



Characters. — This medium-sized and Shrew-like species is 

 sufficiently distinguished from all the foregoing sliort-tailed 

 Opossums by the presence of three dark longitudinal lines 

 running down the back ; the general ground-colour being grey 

 or rufous. There are fifteen pairs of teats, of which five are 

 central. Length of head and body of male about 5! inches ; 

 of tail 2f inches ; female rather smaller, with the tail rela- 

 tively longer. 



Distribution. — B razil . 



Till the publication of the British Museum Catalogue of 

 Marsupials in 1888, this species was almost universally known 

 by the appropriate name of Didelphys tristriata, and since the 

 object of nomenclature is to enable us to recognise and dis- 

 tinguish animals with facility, it seems a pity that a rigid 

 adherence to the rule of priority should have led to the substi- 



