104 MR. O, THOMAS ON RODENTS FROM PERU. [Jan. 17, 
sufficient importance to justify me in describing our specimens as 
new without seeing Mr. Tomes’s type. 
This species, as represented by the specimens before me, is very 
like the European Mus sylvaticus, L., in general appearance, though 
it is considerably larger. Its nearest ally seems to be H. longi- 
caudatus, Benn., which, however, differs from it by its much smaller 
size and by its quite uniform brown or black tail. As all the eight 
specimens of H. albigularis in the collection possess the same bicolor 
tail, it would seem to show that it is as constant a character among 
the New-world Hesperomyes as I have found it to be among the true 
Old-world Mures. H. vulpinoides, Schinz}, a species of about the 
same size, has a quite unicolor tail. This latter, moreover, comes 
from the eastern side of S. America, the types having been collected 
in the province of Minas Geraes. 
6. Hesprromys (CALoMys) LONGICAUDATUS, Benn. 
a-f. Huambo, 3700’, April and May 1880. 
Head and * Forearm Har-conch, Muzzle 
body. Tail, | Hindfoot. andhand. length.  toear. 
a 9.. 3°25 5:0 89 "95 "45 “79 
6. 9 .. 325 5:4 90 98 50 84 
« 9.. 330 5:4 ‘90 ‘98 D5 85 
d. 2.. 290 4:8 89 — "52 ‘78 
This species seems to be the common Mouse of the whole of 
central S. America, as the Museum series contains specimens from 
Ecuador, Peru, Bolivia, Chili, Buenos Ayres, Paraguay, Minas 
Geraes, and Bahia, thus covering an extremely extended range. 
The following is its synonymy, as far I have been able to make it 
out with any certainty :— 
Mus longicaudatus, Benn. P. Z.8. 1832, p. 2. 
Mus (Calomys) flavescens, Waterh. P.Z.S. 1837, p. 19; Voy. 
Beagle, i. Mamm. p. 46, pl. 13 (1839). 
Mus longicaudus, Lund, Blik p. Bras. Dyrev. iii. p. 279 (1841). 
Hesperomys eliurus, Wagn. Archiv f. Naturg. 1845, i. p. 147; 
Abhandl. Akad. Miinch. v. p. 307 (1850). 
It is, however, just possible that Mus longitarsus, Rengg.’, may 
refer to this species, in which case Mr. Bennett’s name would have 
to sink into a synonym, as Rengger’s work was published in 1830, 
two years before M. longicaudatus was described. 
Prof. Burmeister in his recent work on the Mammals of the 
Argentine Republic*, places M. longitarsus as a synomym of A. 
longicaudatus, apparently not noticing that, if they are the same, the 
former name must stand as that of the species. However, the type 
of M. longitarsus, though young, is said by Rengger to have a hind 
? Schinz, Syn. Mamm. ii. p. 193 (1844). H. vulpinus, Lund, nec Licht, 
? Saug. Parag. pp. 231, 232 (1830). 
8 Page 221, 1879. ; 
