neio Neotropical Mammals. 287 



of tail dull pale rusty above, paler below ; first two or three 

 inches of naked part mottled with brown, the rest white. 



Dimensions of type (male) : — 



Hind foot (wet) 44 millira. 



Skull : greatest length 60 ; basal length ^Q ; greatest 

 breadth 35 ; combined length of ma}-^ 8*3. 



Nab. Balzar Mountains, Prov. Guayas, W. Ecuador. 



Ti/pe B.M. no. 80. 5. 6. 87. Coll. Illingworth. Two 

 specimens. 



The uniform pale reddish colour of these specimens is quite 

 peculiar, but there is sufficient resemblance to it in some of 

 the other Museum Philanders to prevent my making the 

 Guayas form into a full species. 



Marmosa Simonsi, sp. n. 



A grey medium-sized species with a white tail-tip. 

 General appearance very like that of M. sinaloce, Allen, 

 although very much larger. Colour above soft pale mouse- 

 grey, clearer on the fore back, becoming rather bufFy poste- 

 riorly. Centre of face pale yellowish white ; dark eye- 

 markings broad, strong, black, extending quite to the ears. 

 Lower cheeks, patch behind base of ears, and whole of under 

 surface pale buffy yellow, the hairs on cheeks and chin this 

 colour to their roots, those on the belly slaty basally. A 

 well-marked chest-gland present. Arms and legs like body; 

 hands and feet silvery white above. Tail clothed with body- 

 fur for rather less than half an inch, then practically naked, 

 grey for its basal three fifths or two thirds, white terminally, 

 as in most of the larger species, the two colours more or less 

 mottled at their junction and below. 



Skull of about normal proportions ; nasals well expanded 

 posteriorly ; supraorbital edges with well-defined ridges and 

 pointed postorbital processes ; middle and posterior premolars 

 about equal in size. 



Dimensions of the type (an adult female, measured by 

 collector in the flesh) : — 



Head and body 130 millim. ; tail 152; hind foot (s. u.) 

 20 ; ear 26. 



Skull : greatest length 34 ; basal length 30"5 ; nasals 14*1 x 

 4*4; interorbital breadth 5*1; intertemporal breadth 6*4; 

 palate length from gnathion 18'2 ; breadth between outer 

 corners of m.^ 11 ; combined length of ms.^~^ 6. 



Hab. Pun^, Pun^ Island, and Guayaquil ; altitude little 

 above sea-level. 



Ti/pe B.M. 99. 8. 1. 20, from Pund. Original number 9. 

 Collected 3rd November, 1898, by Mr. Perry O. Simons. 



20* 



