104 MR. O. THOMAS ON RODENTS FROM PKRU. [Jail. 17, 



sufficient importance to justify me in describing our specimens as 

 new without seeing Mr. Tomes's type. 



This species, as represented by tlie specimens before me, is very 

 like the European Miis sylvaticus, L., in general appearance, though 

 it is considei'ably 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 vvould 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. vuJpinoides, 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. Hesperomys (Calomys) longicaudatus, Benn. 

 a-f. Huambo, 3700', April and May 1880. 



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. S. 1832, p. 2. 



Mits {Calomys) fiavescens, Waterh. P. Z. S. 1837, p. 19; Voy. 

 Beagle, i. Mamm. p. 46, pi. 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 tliis 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 H. 

 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 



1 Schinz, Syn. Mamm. ii. p. 193 (1844). H. vulpimis, Limd, nee JJicht, 



2 SSug. Parag. pp. 2.31, 232 (1830). 



3 Page 221, 1879. 



