94 Field Museum of Natural History — Zoology, Vol. X. 



of female topotype: Greatest length 26.9; basilar length 24.5; zygo- 

 matic breadth 14; nasals 11 X3.2; interorbital constriction 5.6; palate 

 13.9; front of canine to back of M * 11. i. 



Remarks. This species appears to have no very close relative unless 

 it be Peramys adustus of eastern Colombia which, although about the 

 same size, is evidently much paler in color and lacks the extensive 

 buffy pectoral area. Both the type and the one topotype obtained are 

 imperfect, having been injured by ants while lying dead in the traps, 

 the latter so badly that its mutilated body was preserved in alcohol. 



Marmosa madescens sp. nov. 



Type from Tambo Ventija, 10 miles east of Molinopampa, Peru. 

 Altitude about 9000 ft. No. 19689 Field Museum of Natural History. 

 Adolescent male. Collected June 15, 1912, by W. H. Osgood and M. 

 P. Anderson. 



Characters. A mediimi-sized species of very dark color and unbeaded 

 skull, probably allied to M. incana and M. fuscata. Upper parts rich 

 dark brown; back Front's brown shading to Vandyke brown on sides; 

 frontal and interorbital region slightly paler brown; eye ring black, 

 its anterior extension brownish; hairs of cheeks, chin, throat, breast, 

 midventral and inguinal region self-colored creamy buff; hairs of sides 

 of throat and belly and inner sides of arms and thighs creamy apically 

 and broadly slaty basally; midventral area of self-colored hairs occupy- 

 ing about one-fifth the transverse extent of the abdomen; tail thickly 

 clothed with fine short hairs except the distinct scaly prehensory pad; 

 upper side of tail dusky brownish except a short variable white tip; 

 under side of tail irregularly whitish for distal two-thirds of its length, 

 the remainder sooty; front of arms and legs brown; feet and toes whitish 

 at least laterally. 



Skull rather elongate; supraorbital and temporal ridges only faintly 

 indicated; nasals slender and slightly expanded posteriorly. 



Measurements. Type: Total length 259; head and body 120; 

 tail 139; hind foot 19. Skull of type: Greatest length 32.2; basal 

 length 30.9; zygomatic breadth 15.7; least interorbital breadth 6.5; 

 nasals 14.7 x 3.5; palate length from gnathion 17.9; front of canine to 

 back of M ^ 13.5; combined length of Ms ^'' 6. 



Remarks. Although comparison of actual specimens has not been 

 possible, it is evident that this species has its nearest relationship with 

 M. incana and M. fuscata. It differs from fuscata at least in the color 

 of its imderparts and doubtless other characters will be found upon 

 comparison of specimens. 



