80 MR. C. BODEN KLOSS ON 
Apart from smaller size the skull appears to differ from that of 
R. b. magnus in having the palatal foramina protracted backwards to a 
line joining the roots of the first molars, broader teeth and nasals 
truncated posteriorly. 
(or measurements see table postea). 
The other specimens differ from R. b. mullulus in larger size ; 
browner, more warmly coloured upper parts; smaller bullae and upper 
incisors a little more curved toward the throat, but markedly less so 
than in orange-toothed rats. The larger of the two is related to 
R. bowersi (Anderson) from near Bhamo, Upper Burma, and R. ferreo- 
canus ( Miller) from Trang, Peninsular Siam. I have only been able to 
compare it with specimens of the latter, but Mr. Thomas and | have 
noted some differences between the two which, taken together, seem to 
indicate that bowers? is browner, less grey in colour, has the dark areas 
of the feet less extensive, larger bullae but smaller teeth.* In all 
these features Mr. Gairdner’s specimen differs from ferreocanus in the 
same way, and I should call it F. b. bowerst, were it not that the latter 
is described as being “ pale yellow below and on the feet and on the 
tip of the tail, distinctly defined from the darker colour............ This 
species is closely allied to those rats which are distinguished by yellow 
bellies.” It is also figured as yellow below with no distinct line 
between the lower parts and sides, etc.f The present example is 
beneath white, clearly margined from the brown of the sides, as in 
ferreocanus, and I look upon it asa link connecting the two as races of 
one species and name it 
2. Rattus bowersi lactiventer, subsp. nov. 
Type. Adult male from Sikawtur, 40 miles N. W. of Raheng, 
W. Siam, 1500 ft. [ No. 2635/CBK.] Collected by Mr. K. G. Gaird- 
ner, on 21 May, 1917. Orig. No. 433. 
Differs from J. b. bowersi in being white, not yellow beneath, 
and from R. b. ferreocanus in being browner and warmer above and 
with a good deal of white on the feet ; from both in having no pale tip 
to the tail. 
* Thomas, Journ. Bombay Nat. Hist. Soe, XXIV, p. 410 (1916 ); 
Kloss, Records Indian Museum, XIII, p. 5 (1917). 
t Anderson, Anat. & Zool. Researches, p. 304, pl. XVII (1878). 
JOURN, NAT. HIST. SOC. SIAM. 
