new Neotropical MuricUe. 353 



at the roots of the whiskers, just in front of the anterior 

 canthus of the eye. Ears rather small, well-clothed, wholly 

 rust-coloured; but there are a few whitish hairs just behind 

 their posterior bases. Upper surface of hands pale reddish 

 brown, the rusty of the forearm gradually passing into the 

 brown ; on the hind limbs the rusty goes down to and covers 

 the ankles, and passes along the outer side of the foot nearly 

 to the base of the fourth toe ; inwards of this there is a broad 

 whitish patch covering the metatarsals of the first three digits, 

 and beyond this again the basal phalanges of the digits are 

 dark brown all across the foot, while the terminal ones are 

 whitish; fifth hind toe long, reaching almost to the middle of 

 the second phalanx of the fourth. Tail very long, thinly 

 haired, uniformly daidc brown. Mamma? 2 — 2 = 8. 



Skull long, rather narrow, with well-defined beaded but 

 not overhanging supraorbital edges ; interparietal large ; 

 palatal foramina long and open. Molars broad, rounded, 

 their cusps unusually high and prominent, not apparently 

 wearing flat with age. 



Dimensions of the type (a well-made skin) : — 



Head and body 148 millim. ; tail 187 ; hind foot (moistened) 

 32"5 ; ear (moistened) 17 x 14. 



Skull : lambda (front of interparietal) to nasal tip 32, 

 greatest breadth 19 ; nasals 14 x 4*3 ; interorbital breadth 5 ; 

 interparietal (in another rather larger specimen), length 5"2, 

 breadth (c.) 11*5 ; length of outer wall of infraorbital foramen 

 3; palate length from henselion 15*1 ; diastema 93 ; palatal 

 foramina 7*8 x 2*9 ; length of upper molar series 5'9. Lower 

 jaw : condyle to incisor-tip 22 ; height of ramus below ^n 5. 



Hab. Rio Janeiro. 



Type: B.M. 76.12.8.3. 



Of this very handsome species the Museum possesses three 

 specimens, and as these came from three different dealers at 

 different times, there are probably many others in the various 

 European museums. One of the specimens came with the 

 alternative names of Mus vulpinus, Brants *, and M. leuco- 

 gaster, Brandt f, and the next with that of M. cinnamomeus, 

 Pictet J. The hind foot of the new species being, with the 

 claws, 1 inch 3 lines French measure in all three specimens, 

 it is clear that "Mus vulpinus" with a hind foot of over 

 2 inches, and M. leucogaster, with one of 1 in. 7 lin., are both 

 too large, just as M. cinnamomeus, with one of 1 in. lin., is too 

 small. M. leucogaster is " e flavo fuscus ," and has its" cauda 



* Het Gesl. der Muizen, p. 137 (1827). 



t Mem. Ac. Petersb. (6) iii. pt. 2, p. 428 (1835). 



X Anim. Nouv. Mus. Genev. p. 64 (1841). 



