1. DIDELPHYS. 333 



crisp. General colour greyish brown, more or less suffused, especially 

 on the sides, with yellowish or rufous. Face brown or rufous 

 brown, darker round the eyes; a prominent white or pale yeUow 

 spot above each eye, much smaller in area than in B. opossum. 

 Ehinarium with one pair of lateral notches below. Ears (PI. XXVI. 

 fig. 2) very large, broad and rounded, naked, translucent, laid 

 forward (in spirit-specimens) they reach beyond the anterior canthus 

 of the eye ; their anterior base with a well-marked projection, their 

 inner margin unusually convex in its lower half; their colour 

 uniform dark slaty grey. Metatragus small. Belly pale yellowish 

 white, rather sharply defined from the dark upper colour, a more or 

 less distinct yellow line running along the junction, of the two 

 colours. Pouch rudimentary or absent. Mammae 4-1-4=9*. 

 Front of fore andoutsides of hind limbs, inner side of lower leg, hands 

 and feet pale brown. Fee|t narrower and more elongated than in 

 D. opossum ; pads (PI . XXVI. fig. 3) very distinctly defined, the pollical 

 and hallucal generally continuous, undivided. Fifth hind toe barely 

 reaching to the middle of the second phalanx of the fourth. Tail 

 unusually long in proportion ; about one inch of its base alone furry, 

 the remainder scaly, with a few short hairs between the scales ; its 

 colour brown, changing to white terminally. 



Slcull with very much the same general proportions as in D. oposswm, 

 but the interorbital region is broader, and the postorbital processes 

 are reduced to mere faint excrescences on the supraorbital ridges, 

 and even these do not appear until advanced age. The temporal 

 crests are also much later developed than in the other aUied species. 

 Palate more perfect than in D. opossum, the posterior smaller pair of 

 vacuities being, as a rule, absent, and the anterior pair smaller. 

 Posterior nares comparatively broad. 



Teeth as in D. opossum, except that they are, as a whole, lighter 

 and more delicate ; the upper premolars especially are markedly 

 thinner transversely than in that species. 



Dimensions. 



2- 



a (in spirit). 



tnillim. 



Head and body 240 



TaH 300 



Lower leg 67 



Hind foot 43-5 



Ear 25 



Muzzle to eye 28 



Skull, see p. 341. 



Hab. Neotropical Eegion, from Costa Eica to Brazil. 

 Type in the Paris Museum. 



* One adult female in spirit only examined. 



