1879.] MR. E. R. ALSTON ON ACANTHOMYS LEUCOPUS. 645 



29. Ornismya longirostris, d'Orb. & Lafr. Syn. Av. ii. p. 29. 



Guarayos (0.). 



No specimen in Paris Museum (Elliot, I. &). 



30. Noctuaferox, d'Orb. & Lafr. Syn. At. i. p. 8 ; d'Orb. Voy. 

 Ois. p. 127. 



Prov. Chiquitos (0.). 



31. Ibycter gymnocephalus, d'Orb. & Lafr. Syn. Av. i. p. 2; d'Orb. 

 Voy. Ois. p. 50. 



Cocbabamba (0.). 



3. On the Acanthomys leucopus of Gray. 

 By Edward R. Alston, F.L.S,, F.Z.S., &c. 



[Keceived June 3, 1879.] 



In the first part of Prof. Schlegel's new periodical, • Notes from 

 the Royal Zoological Museum of the Netherlands at Leyden,' Dr. 

 F. A. Jentink identifies two specimens of a spiny Rat from Celebes 

 with the North-Australian species described by the late Dr. Gray 

 under the name of Acanthomys leucopus \ The specific identity of 

 a Mus from Celebes with one from the continent of Australia seemed 

 so unlikely that I suspected that Ur. Jeutink might have been misled 

 by Gray's very insufficient description ; and I was consequently induced 

 to reexamine the types in the British Museum. A comparison of 

 the description given below with that of Dr. Jentink will show that 

 the two species are evidently quite distinct, the Celebes animal being a 

 fourth smaller than the Australian, with much smaller feet, and 

 having the tail longer than the head and body, thinly haired and 

 tufted, instead of shorter and naked. 



In a note to my report on the Rev. G. Brown's collection, I re- 

 marked that Gray's species belonged to the restricted genus Mus 

 and not to Acanthomys, Lesson (=Acomys, Geoffroy), and that it 

 would require to be renamed, the specific name being preoccupied 

 by the common North-American White-footed Mouse, the Mus leu- 

 copus (Rafinesque) of Desmarest and other writers, Hesperomys leu- 

 copus of more recent zoologists 2 . Dr. Jeutink also places the Aus- 

 tralian species in the genus Mus, but on different grounds ; he 

 rejects the genus Acomys or Acanthomys altogether, as being founded 

 merely on the superficial character of the possession of spinous hairs. 

 But that group was founded by the older Geoffroy on the Mus 

 cahirinus of Desmarest ; and it has been restricted by subsequent 

 writers to the small group of Ethiopian Mures in which a spiny 

 coat is combined with marked cranial peculiarities, notably with 

 shallow pterygoid fossae, very small incisive foramina and slightly 

 developed coronoid processes 3 . 



1 P. Z. S. 1867, p. 598. 2 P. Z. S. 1877, p. 124, footnote. 



3 Cf. Peters, Eeise n. Mozambique, i. p. 161 ; Alston, P. Z. S. 1876, p. 83. 



