158 Mr. O. Thomas on new /S/>f?cies o/'Didelphys. 



Seven specimens. 



Mus salamonis, Earns., from Florida Island, is again a much 

 smaller species, with a hind foot only 44 millim. in length. 



Mus prcetor^ sp. n. 



General characters, size, colour, spininess of fur, size of ears, 

 &c., as in M. terrce-regince, Alst., but distinguished by its 

 proportionally shorter hind feet, shorter tail, and by having 

 two pairs of pectoral mammse, its mammary formula being 

 therefore 2 — 2 = 8 instead of 1 — 2 = 6. 



Dimensions (in spirit) : — 



Head and body. Tail. Hind foot. Ear. 



millim. millim. millim. millim. 



Male 188 134 35-5 1.5-5 



Female (type) .... 168 118 33-5 15 



Skull ( 2 ) : basal length 37*5 millim., greatest breadth 22 ; 

 length of upper molar series G'G] palatal foramen, length 7"4. 

 Two specimens. 



XIX. — Diagnoses of four new Species o/' Didelphys. 

 By Oldfield Thomas. 



Didelphys [Micoureus) lepida^ sp. n 



Closely allied to D. murma, L., but distinguished by its 

 much smaller size, and by the shortness of its ears, which, 

 when laid forward, barely reach to the centre of its eye. 



Dimensions of the type (an adult female, skin) : — 



Head and body 105 millim.; tail (imperfect, more than) 

 105 ; ear, above head, 9*0 ; first three molars, combined 

 lengths 4-7. 



Hab. Peruvian Amazons {E. Bartlett). 



Didelphys {Peramys) scalops^ sp. n. 



Size of D. hrevicaudata, Erxl. Head, rump, and tail bright 

 rufous ; fore back, shoulders, and belly grizzled olive-grey. 

 Skull long and narrow ; teeth very small. 



Dimensions (male, skin) : — 



Head and body 183 millim. ; tail 71 ; ear 8*0 ; skull, length 

 33 ; combined lengths of first three upper molars 4' 9. 



Hah. Brazil. 



