1(10 Mr. 0. Thomas on 



" broccoli-brown " ; lateral areas also dark ; hips and sides of 

 rumj) prominently dark cinereous ^rey (" slate-grey "). 

 Under surface soiled yellowish, all the hairs except those oa 

 the chin broadly slaty basally. 

 Hah. Tucuman [Dinelli). 



4. Marmosa elegans (typical). 



Bather larger than the other subspecies and more variable 

 in general colour. Dorsal area " drab " or greyer. Under 

 surface white to the roots of the hairs along the middle line, 

 nearly or quite to the anus ; sides of belly grey mixed. 



Hah. Chili; Valparaiso [Danoin, Wolffsohn). 



Further south still, in Valdivia, occur the forms described * 

 as Didelphys australis, F, Philippi, and D. soricina, R. A. 

 Philippi, but I have not as yet seen specimens of either. 



Detailed Descriptions of the new Forms. 

 Marynosa elegans venusta. 



Size rather less than in typical M. elegans. Fur very soft 

 and fine, about 10 millim. long on the back. General 

 colour of dark dorsal area soft fawn-grey, perhaps most 

 nearly approaching Ridgway's " wood-brown." Forehead 

 darker, in continuation with a narrow median frontal line. 

 Eye-rings black. Cheeks below eye prominently white, as 

 are the lips and chin. Light lateral bands generally well 

 defined, pale fawn. Under surface almost uniformly soiled 

 yellowish white, the hairs white to their bases only on the 

 chin and middle line of the throat and chest, slaty at base 

 everywhere ei>e, the slate showing through. Ears large and 

 leafy, practically naked. Hands and feet pure white ; outer 

 side of arms like body, inner side like belly ; hinder side of 

 legs rather greyer than the rump, but not contrasting 

 markedly with it. Tail uniformly thinly haired, pale brown 

 above, white on the sides and below. 



Skull as in typical elegans ; no trace of supraorbital ric 

 or processes ; the nasals not expanded posteriorly. 

 Dimensions of the type (measured in the flesh) : — 

 Head and body 105 millim.; tail 118 

 c. u. 16 ; ear 23. 



Skull; basal length 27-5; zygomatic breadth 17; nasals 

 12*7 X 2*2; combined length of three anterior molariform 

 teeth 4-8. 



Hah. Paratani, W. of Cochabamba, Bolivia. Altitude 

 2800 m. 



* Arch. f. Nat. 1894, pp. 33 & 3C., pi. iv. 



