MAMMALS COLLECTED IN SIAM. 379 
Type. Adult female (skin and skull) No. 2261/CBK. Col- 
lected on Koh Lan, Inner Gulf of Siam on 29th October, 1916, 
Measurements, See table postea. 
38. Rattus rattus kramensis, subsp. nov. 
Specimens examined, 33 ad., 2% ad. Koh Krain, Inner Gulf 
of Siam. 
Diagnosis, Colour consistent above anda shade deeper 
than in A. r. lanensis, but without any faint yellow tinge below ; 
underparts tinged with pale grey at the sides, feet slightly yellow- 
ish. Skull very similar to the mainland form but the zygomata and 
infraorbital plate averaging a little wider; scutes of tail coarser. 
Type. Adult female (skin and skull) No, 2281/CBK.  Col- 
lected on Koh Kram, Inner Gulf of Siam on 30th October, 1916. 
Measurements :—See table postea. 
39. Rattus rattus mesanis, sub p. nov. 
Specrmens examined :-—11 5 ad., 112 ad., 5 imm. and juv. 
individuals from Koh Mesan, near Cape Liant, S. E. Siam. 
Diagnosis, Colour practically consistent above and as in 
medium animals from the mainland; below white, sometimes shght- 
ly grey at the sides; feet very white. About the same size as 
R, vr. portus mihi, but the supraorbital ridges more pronounced and 
angular, nasals a little smaller, palatal foramina larger and the 
tooth-rows hardly diverging posteriorly. About the same size also 
as R. vr. mekensis mihi, (P. Z.S., 1916, p. 55), from the Chantabun 
Archipelago, but skull narrower and palatal foramina smaller, bullae 
larger, parietal ridges more parallel, colour rather less darkened above 
mesially, the undersurface, if silvered, much less so and the metapo- 
dials without dark centres. 
Type :—Adult male (skin and skull) No. 2320/CBK. Collec- 
ted on Koh Mesan Island near Cape Liant, $8. E. Siam on 2nd Novem- 
ber, 1916. 
Measurements. See table postea. 
40. Rattus rattus koratensis, subsp. nov. 
Specimens examined :—12 ad., 12 mm. from Lat Bua Kao, 
East Siam, 
VOL. LI, NO. 4, 1919. 
