Journal of the Federated Malay States museums - Sabrizain.org

66 Journal of the F.M.S. Museums. [Vol. VII,
Rattus rattus batin, subsp. nov.
Type:—Adult male, aged (skin and skull). Collected at
Mentigi, West side of Pulau Mapor or Panjang, Rhio Archipelago,
on June 6th, 1915, by H. C. Robinson. Federated
Malay States Museums No. 304/15.
Characters:—A member of that section of the Epimys
rattus group, characterized by somewhat slender feet, hispid,
but not very spiny pelage and marked development of long
black piles on the lower back. Separable from the form*
inhabiting the adjacent islands of Bintang and Battam by the
very much lighter colour above and by the somewhat larger
bullae.
Measurements:— External dimensions of the type, taken
in the flesh: head and body, 208(180); tail, 218 (195); hindfoot,
355 (34), ear 22 (20-5). Extremes of eight specimens,
head and body, 171-208; tail. 193-218; hindfoot. 33'5-35'5 ;
ear, 20-22.
Cranial measurements ot type: greatest length, 44-4
(44'o) ; condylo-basilar length, 39-0 i'39'o) ; diastema, 12-4
(i2 -
g) ; zygomatic breadth, 20'o
-
(20 i) ; median length of
nasals, i6'0 (16-3) : upper mlar series. 6"8 (6*9).
Extremes of twelve specimens; greatest length. 4i'5-44"4;
-
condylo-basilar length, 36'3-39'o; diastema. n 6-i2"6;
zygomatic breadth, i8"8-2r2: median length of nasals,
i4 -
o-i6'i ; upper molar series. 6-5-7-2 mm. For detailed
measurement see table on p. 69.
Specimens examined:— Fifteen, from the east and west
sides of Pulau Mapor.
Remarks:—The series examined, which was trapped both
in old jungle and in the vicinity of the huts of the some what
primitive orang hint people inhabiting the island are fairly
uniform, the principal variation being in the degree of
distinctness in t lie line of separation of the light undersurface
from the flanks. The race closely resembles a form, as vet
un-named, inhabiting the western islands of the Archipelago
but appears to be somewhat mure robust. The intrusion in
the central islands of a race, R. r. rhionis which closely resembles
the north European R. rattus rattus is a curious and
as yet unexplained fact.
'Mus rattus rhionis, Tbos & Wrought Ann. and Mas. Nat. Hist. (8) iii,
p. 441 (1909). Measurements in parentheses are those of an adult male
topotype of Mus rattus rhionis, Thos & Wrought F.M.S Mus. No. 2086/0S.