452 MR. O. THOMAS ON A COLLECTION OF [JuilC 17, 



colour of back continued down on to the metacarpals and 

 metatarsals. Ears without a projection. Tail quite unicolor, dark 

 brown, clothed throughout with elongated hairs, forming a distinct 

 pencil at the tip. Feet broad, the pads very large and smooth ; 

 the proximal two so broad as to touch each other. Fifth hind toes 

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

 IMammse six ; one pectoral and two inguinal pairs. Interdental 

 palate-ridges six. 



Two specimens in the collection, undoubtedly referable to 

 Tschudi's species, show such differences from the specimen from 

 Huainbo, named by me in 1882 H. leucodactylus, that 1 am 

 inclined for the present to consider that, after all, Mr. Tomes's 

 species H. latimanus, with which M. Stolzmann's specimen agrees, 

 should remain as a good species, and is not synonymous with 

 li. leucodactylus, as I had considered it. 



Judging only from the specimens I have seen, H. leucodactylus 

 may be distinguished from H. latimanus by its larger size (see 

 dimensions above), especially its much larger feet, its more bushy 

 tail, larger teeth, both absolutely and relatively (see skull- 

 dimensions), and by the presence of six instead of five interdental 

 palate-ridges (see Plate XLIV. figs. G & 7). It is of course possible 

 that specimens will yet be found intermediate between the two 

 forms, in which case they will again have to be united. 



3. Hesperomys (Oryzomys) laticeps, Lund. S. No. 4. 

 a to Z. Twelve specimens. Junin and Amable Maria. 



*IIesperomys laticeps, var. nitidus, var. nov. (Plate XLII. 

 fig. 1.) 



a to ?'. Eighteen specimens, mostly young. Junin and Amable 

 Maria. 



These specimens are readily separable at sight from the ordinary 

 H. laticeps, more resembling H. alhiyularis. Tomes, or H. vulpinoides, 

 Schinz, in their general appearance ; but a closer examination shows 



