A NEW SPECIES OF MOUSE. 
Dimensions of skull. — Greatest length, 32 mm. ; basal length, 27 mm. ; 
greatest breadth, 16 mm. ; nasals, 11.8 x 4 mm. ; interorbital breadth, 5 mm. ; 
width of braincase, 14 mm. ; palate length, 15.8 mm. ; diastema, 8 mm. ; 
palatal foramina, 6x2 mm. ; upper molars, 5.5 mm. 
Habitat. — Otway Forest, Victoria. Type locality Turton’s Pass. 
Type. — Adult male in National Museum of Victoria, C197. 
Dimensions of a second male, C198. — Head and body, 114 mm. ; tail’ 
124 mm. ; hind foot, 28.8 mm. ; ear, 21 mm. 
Remarks. — The group was previously known by species from 
West Australia ( albocinereus Gould [1] and a. squalosum Thomas 
[2]), south-eastern South Australia ( apodenioides Finlayson [3]), 
and southern Queensland ( glaucus Thomas [4]), the largest being 
albocinereus. The much greater size of the present animal, its 
relatively longer feet and ears, and its larger teeth, distinguish 
it from other species. 
The two specimens were trapped in forest country with a 
thick undergrowth of scrub which is literally riddled with the 
“runs” of Rattus assimilis Gould. Though a search was made 
no small burrows were discovered, and it seems probable that 
the mouse makes its home in fallen logs. 
Genus MASTACOMYS Thomas 1882. 
Mastacomys fuscus Thomas. 
Mastacomys fuscus Thomas, Ann. Mag. Nat. Hist. (5), IX, p. 413, 1882 ; 
id. Ann. Mag. Nat. Hist. (9), X, p. 550, 1922 ; Lydekker, B. M. Cat. 
Fos. Mamm., 1, p. 227, 1885 ; Ogilby, Aust. Mus. Cat. No. 16, Aust. 
Mamm., p. 120, 1892 ; Wood Jones, Mamm. Sth. Aust., Ill, p. 323, 
1925; Finlayson, Trans, and Pro. Roy. Soc. Sth. Aust., LVII, 
p. 125, 1933. 
In the National Museum are five skins (with skulls)*, one 
spirit specimen, and one separate skull of Mastacomys. The 
skull was found in a sand drift on Swan Island in 1905, three 
Victorian specimens were taken in 1918, and a fourth was 
trapped in November of last year. Of the remaining skins one 
is labelled “West Coast of Tasmania, 1872,” the other has no 
data preserved. Thomas (loc. cit.) recorded an immature 
female from Victoria, but the whereabouts of the specimen has 
been in doubt ; Mr. M. A. C. Hinton, deputy Keeper of Zoology 
at the British Museum, has kindly cleared up the matter, and 
says in a letter “it is B.M. No. 92.4.23.1, collected in Gippsland 
(no more precise locality given) . . . H.F. 25 mm., E. 13 mm., 
measured on skin in relaxed condition. It is quite a baby, 
molars just coming into wear.” 
* Recently prepared from specimens preserved in alcohol. 
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