120 TREUBIA VOL. II, 1. 
2. Mus (musculus?) ouwensi, nov. 
Above dark brown very finely grizzled with ochraceous; bases of hairs dark grey: 
face and top of muzzle slightly tinged with ferruginous. 
Underparts not sharply margined, white throughout or very pale silvery white: 
bases of hairs grey. Feet white. Tail dark above and pale below. Mammae 3 — 2 — 10. 
Type. Adult male (skin and skull) collected at Probolinggo, East Java by Lim 
King Siang on 15th February, 1915. No. 173. 
Specimens examined. Seven skins and skulls and eight individuals in 
alcohol from Rembang, Probolinggo and Temanggoengan, E. Java, and two skins and 
skulls from Pamekasan, Madoera Island. 
The two examples from Madoera have a small white spot on the forehead; but 
otherwise do not differ from the others. 
External measurements taken in the flesh. An average alcoholic 
specimen: head and body, 55; tail 62; hindfoot, s.u., 15; ear from meatus Il mm. 
The largest specimen: head and body, 60; tail, 68; hindfoot, 16; ear 13 mm. 
Skull of the type. Greatest length, 21.0; Condylobasilar length, 19.0; basilar 
length, 17.3; palatilar length, 9.6; diastema, 5.5; upper molar row (alveoli), 3.3; length 
of palatal foramina, 4.4; length of nasals, 7,0; interorbital breadth, 3.6; cranial breadth, 
9.6; Zygomatic breadth 11.0 mm. 
Remarks. In spite of the fact that this animal is found in Java 
and Madoera with M. m. homourus | hardly care to regard it as a distinct 
species for the skulls and teeth of both are exactly alike: the difference 
lies only in the colour. Therefore I leave its rank undecided for the present. 
Major P. A. OUWENS, Curator of the Zoological Museum, Buitenzorg, 
who was the first to collect it and after whom it is named, knows it well 
in life and states that instead of running like the common house-mouse 
it progresses by a series of leaps. Mus ouwensi is a field mouse. 
III. House-rats. 
1. Rattus rattus diardi. 
Mus diardi JENTINK, Notes Leyden Museum, II, 1880, p. 13 (West Java). 
Mus griseiventer BONHOTE, Fasciculi Malayenses, Zool. 1, 1903, p. 30, 
pl. II fig. 3, pl. IV fig. 5 (Perak, Malay Peninsula); DAMMERMAN, Mededeel. 
Lab. v. Plantenziekten, No. 24, 1916, pp. 1, 7—9 (Java). 
Rattus griseiventer? ROBINSON & KLOSS, Journ, Fed. Malay Sines 
Mus. VII, 1919 p. 280 (Sumatra). 
1 %¢3 © Onrust Id. near Batavia, Java 
3 © Pandeglang x, 
© Cheribon | 
Q Soerabaya by 
Kaligoea * 
Q Pamekasan Madoera 
Q Boeleling Bali 
Q Kloengkoeng “ 
Q Laboean Amok 
1) 
