Descriptions of East Asiatic Mammals 293 
heavily spinous and have the tail shorter than the head and body. 
Although the original R. whiteheadi is from Borneo, the group 
is present also on most of the other Sunda Islands and from the 
Malay Peninsula to Siam. In Perak the form R. inas is found, 
in Johore R. klossi, in lower Siam R. asper, and in eastern Siam 
R. sakercttensis. The colors are a mixture of blackish and rufes- 
cent on the back, "pinkish buff" beneath. The length of the head 
and body is about 4% inches, tail 4 inches, hind foot 1 inch. 
q. The Alexandrine Roof or rattus Rats group, Rattus 
rattus and relatives (with white-tipped gray ventral hairs), in- 
cludes a large number of often poorly distinguishable races. The 
headquarters of this group, as is the case with the entire genus, 
is southeastern Asia. Although no attempt can be made in this 
place to describe more than a few representative forms, it should 
be understood that many additional local races are known. The 
R. rattus group in the Orient comprises coarse-haired, some- 
times weakly spinous Rats of the general size of the Roof Rat 
(already described) or a little smaller. The tail is usually longer 
than head and body, as in R. r. alexandrinus, but it may be 
shorter, as in R. flavipectus. The color too is variable — brown- 
ish gray in some, reddish brown in others. 
The following are members of the gray-bellied R. rattus 
group : R. r. diardi from the Malay Peninsula, R. r. thai from 
central Siam, R. r. robustidus and tikos from Tenasserim, R. r. 
tatkorensis from the west bank of the Chindwin River, R. r. 
rattoides, brunneus, and brunneusculus from Nepal, R. r. slch 
deni from Yunnan, R. flavipectus from Yunnan, Tibet and 
Assam, Tonkin and Laos, R. r. molliculus from central Annam, 
R. r. exiguus from Fukien, R. r. hainanicus from Hainan, R. 
losea from Formosa, R. tanezumi from Japan. 
In the majority of the races the tail exceeds the head and 
body in length. A few examples of size follow : Roof rat, head 
and body 7 to 8 inches, tail 8 to 10 inches, hind foot 1% to 1% 
inches; diardi, 7%, 7, 1% ; tikos, 6%, 7y 2 , 1% ; sladeni, 6% to 
