354 Mr. 0. Thomas on some 



in individuo exsiccato albida, in vivo carnea." M. ctnna- 

 momeus has a " teinte generate j'aune" and a tail only 121 

 millim. long. 



Of other species the nearest seems to be Hesperomys rus- 

 satus, Wagn.*, but this has " cauda corpore paululum breviore, 

 . . . pallida" and u pedibus albidis." Mus physodes, Licht.f, 

 which our specimens had been formerly supposed to be, 

 proved, on a personal examination of the type in the Berlin 

 Museum, to be quite a different animal, coloured more like 

 Oryzomys laticeps, Lund. One other species needs mention, 

 namely Mus vulpinus, Lund J, nee Brants, on which M. vul- 

 pinoides, Schinz§, and Calomys laiiceps, Winge ||, nee Lund, 

 are based ; but this is shown by Winge's admirable figures 

 to be again more nearly allied to the true 0. laticeps than to 

 the animal before us. 



Oryzomys xanthceolus, sp. n. 



Size and general characters of 0. galapagoensis, Waterh., 

 to which I had previously assigned it. Fur harsher and 

 shorter than in that species, the hairs on the back about 10 

 or 11 millim. in length. General colour coarsely grizzled 

 yellow and black, the mixture approximating to tawny olive 

 of Ridgway. Cheeks and sides clearer yellow, or rather 

 buff. Under surface white, the slate-coloured bases of the 

 hairs scarcely showing through ; line of demarcation on sides 

 well defined. Eyes with a rather lighter ring surrounding 

 them. Ears large, their substance apparently brown, thinly 

 clothed with yellowish hairs. Hands and feet very thinly 

 haired, almost naked, their few scattered hairs white ; fifth 

 hind toe (without claw) reaching to the middle of the first 

 phalanx of the fourth. Tail very long, thinly haired, brown 

 above and whitish below. 



Skull with a short broad muzzle, sharply edged and beaded 

 supraorbital margins, and medium palatal foramina, about 

 equal in length to the upper molar series. 



* Abb. Ak. Munch, v. p. 312 (1850). 

 . t Darst. Saug. pi. xxxiv. (1827-34). 



% Blik Bras. Dyrev. pt. iv. p. 63 (1842). 



§ Syn. Mamm. ii. p. 193 (1845). 



|| Rodents of Lagoa Santa (E Mus. Lundii), 1887, p. 143. Dr. Winge, 

 ■with sublime disregard of the nomenclature rules which other people find 

 it necessary to obey, has shifted the name laticeps from the species to 

 ■which Lund gave it (dubbing that saltator), and assigned it to the form 

 ■which Lund had called vulpinus. The change is, of course, perfectly 

 invalid, and cannot be recognized by any one who acknowledges the prin- 

 ciple of priority. 



