1902.] Allen, Opossums of the Genus Didelphis. 269 



without black tips to the longer hairs. Face markings white and 

 black, strongly contrasted and sharply defined; the V-shaped median 

 black stripe begins about opposite the anterior corner of the eyes and 

 runs back to the occiput, merging on the nape with the black-tipped 

 underfur of the dorsal region. The lateral face marks begin at base 

 of whiskers, midway between nose and eye, running back to enclose 

 the eye, but terminating just behind it as a well-defined spot; sides 

 of the head behind the eye-streak more or less suffused with dusky, 

 forming an ill-defined band for about half the distance from eye to ear, 

 produced by the tips of the hairs being tinged with blackish ; a broad 

 white band behind this dusky extension of the eye-streak joins the 

 white of the cheeks with the broad supraloral white band. Ears 

 apically white, the basal third more or less dusky but not black. Fore 

 and hind limbs and basal half (or more) of tail black; the apical 

 portion of tail white or very light flesh-color. 



Young. Similar to the adult, except that the eye-stripe runs 

 posteriorly to the base of the ear, where it becomes somewhat expanded 

 vertically. 



Measurements. An adult male, Goya, Argentina (R. Perrens) : 

 Total length, 673 mm.; head and body, 378; tail, 295; hind foot,, 41; 

 ear, 55. An adult female, Chaco, near Ascuncion, Argentina (Messrs. 

 Swan): Total length, 653; head and body, 378; tail, 311; hind 

 foot, 43; ear, 52. Skull: Old female, total length, 85; basal length, 

 77; zygomatic breadth, 43.5; length of nasals, 38; postorbital pro- 

 cesses, 15.5; postorbital constriction, 9.6; occipital breadth, 26; 

 breadth at canines, 15; upper toothrow, 29; molar series, 16. Another 

 old female skull and an adult male skull, same locality, both more or 

 less imperfect, present practically the same measurements. 



An adult female from southern Minas Geraes (Rio Jordao, A. Robert) 

 gives the following external measurements: Total length, 650; head 

 and body, 360; tail, 290; hind foot, 40; ear, 53. 



Specimens examined: 



Argentina: Chaco, near Asuncion, 5; Tucuman, i; Goya, 10, 

 mostly half grown or younger. 



Brazil : Lagoa Santa i (topotype of D. albiventris Lund) ; Rio 

 Grande do Sul, 3 (including topotypes of D. lechii Ihering) ; Rio 

 Jordao, southwestern Minas Geraes, 3. 



Total, 23; coll. British Museum. 



So far as the material at present available indicates, the 

 south Brazilian animal may well be referred to true para- 

 guayensis. Lund's D. albiventris was based on the light phase 

 with a white belly, with which Wagner has himself identified 

 his later-described D. poscilotis. Wagner's D. leucotis is a new 

 name for D. azarce Rengger, which is the true paraguayensis . 



