196 Bulletin American Museum of Natural History. [Vol. XIII, 



loins posteriorly ; whole upper surface of the head, excepting the ' eye-spots,' 

 deep brownish black, passing into deep black on the nape, where it joins the 

 well-defined black dorsal line ; cheeks and supraloral spots straw-color ; poste- 

 rior base of the ears fulvous gray, forming an ill-defined patch ; outer surface of 

 the limbs in general like the sides of the body, passing into dusky on the fore- 

 arms ; whole lower surface pale yellowish white, this tint a little stronger on the 

 breast and throat ; ears light brown, apparently flesh-color in life for the ba- 

 sal fourth ; fore feet brown proximally, toes nearly bare, flesh-color ; hind feet 

 dark brown, the toes sparsely haired, light brown ; tail dark brown proximally 

 on the upper surface only, becoming gradually lighter towards the tip, the api- 

 cal third being dull whitish ; less than half an inch of the basal portion is 

 clothed with short fur like that of the adjoining portion of the body. The 

 pouch is indicated in the skin by an area about 50 mm. in length by about 25 

 mm. in width clothed with short, crisp, woolly hairs of a dark rusty brown 

 color, in strong contrast with the rest of the ventral surface. The number of 

 mammae cannot be distinguished. 



Measurements. Total length, 500 mm.; head and body, 240 ; tail, 260 ; hind 

 foot, 43. 



Skull, total length, 55 ; basal length, 51 ; nasals, 26 ; palate, 30; zygomatic 

 breadth, 26.5; mastoid breadth, 21.5; least interorbital breadth, 14.5. The 

 skull is of the usual form for the genus and calls for no special comment. 



This species is distinctly indicated by Tschudi (/. r.), under 

 the name " Didelphys myosurus Temm." After citing Temminck's 

 description he notes that his specimens do not wholly agree in 

 coloration with examples from Guiana and Surinam, they being 

 much more intensely colored, as is the case with many other 

 Peruvian animals in comparison with their east coast representa- 

 tives. The difference is often so considerable, he says, as to 

 many times tempt one to recognize them as distinct species. 

 Metachirus tschudii is undoubtedly the western representative of 

 Temminck's D. myosurus, which, rightly or wrongly, is commonly 

 synonymized with E. Geoffroy's D. nudicaudata. 



Metachirus nudicaudatus colombianus, subsp. nov. 



Type^ No. 15448, $ ad., Donamo, Santa Marta District, Colombia, April 20, 

 1899 ; coll. H. H. Smith. 



Above dark yellowish brown, strongly varied with black, which forms a 

 fairly well defined blackish median area ; sides uniform yellowish brown ; 

 head brownish black, passing into black on the top of the head and nape and 

 around the eyes, which are broadly margined with black ; supraocular spots 

 deep buff ; fur at base of the ears above rusty buff ; cheeks buff, a little paler 

 than the eye-spots ; below white, tinged faintly with yellowish, more strongly 



