292 Mammals of Eastern Asia 
tips. Here come the remaining species groups of Rattus: R. eha, 
R. concolor, R. whiteheadi, R. norvegicus, and R. rattus. These 
can be separated from one another by differences of size, color, 
degree of spininess. 
n. The Spectacled Mountain Rats, Rattus eha group, are 
clad in very soft, dense fur, colored reddish brown above, gray- 
ish white beneath, with the bases slate-gray. The line of demar- 
cation along the flanks is distinct. Dark rings around the eyes 
are extended forward to meet at an acute angle near the tip of 
the nose. The tail is dark above, white beneath, the fine hairs 
covering it becoming somewhat longer toward the tip. The 
length of the head and body is 4% inches, tail 7% inches, hind 
foot 1 inch. This form occurs at 8000 feet in Sikkim. A relative 
from Yunnan, R. e. ninus, is colored less brightly reddish and 
the marks on the face are indistinct. 
o. The Little Burmese Rats, Rattus concolor group, are 
quite small brownish Rats with dirty whitish gray underparts 
(the bases darker) and 8 nipples in females. The length of the 
tail slightly exceeds the head and body. This group is enor- 
mously developed among the islands of the western Pacific and 
even reaches Hawaii, the Tuamoto Archipelago, and New Zea- 
land. On the Asiatic mainland typical concolor is widely distrib- 
uted from Singapore through the Malay Peninsula into lower 
Burma, Laos, and Annam. The length of the head and body is 
about 3 inches, tail 4 inches, hind foot % to 1 inch. This is the 
most mouse-like of all Rattus, though its feet are much larger 
and its hair coarser than in Mus. In Asia it is suspected to be a 
disease-carrier, since it often lives in the thatches of native 
houses. The form found in New Guinea and nearby islands is 
known to be one of the hosts of the mite Trombicula, which is 
the vector of the rickettsial disease known today as scrub typhus. 
p. The Short-tailed Lesser Spiny Rats or Whitehead's 
Rats, Rattus whiteheadi group, are a distinct group of small 
Rats about the size of those in the R. concolor group. All are 
