378 MR. C. BODEN KLOSS ON 
sometimes tinged with grey on the sides and middle line; feet 
white ; a considerably brighter coloured series than that I previous- 
ly obtained in 8. E. Siam. Mammae 3 - 2—10. 
There is a noticeable amount of individual variation, but I can 
see no constant differences amongst the rats of this kind from the 
southern parts of Siam, the Malay Peninsula, Sumatra and Borneo ; 
and it seems most adviseable therefore to regard all as R. r. neg- 
lectus. There are, however, marked tendencies for animals from the 
west and north of Siam to be yellower and brighter than those from 
the south and east, which are browner and duller and more nearly 
agree with neglectus (jalorensis Bonhote, of the Malay Peninsula ); 
while the former Rattus rattus thai mihi! with 3-3 = 12 
mammae ) approximate to sladeni Anderson, from the neighbour- 
hood of Bhamo, which also has 3-3 = 12 mamimae but smaller bul- 
lae. Sladeni is possibly very close to robustulus Blyth, from Schwe- 
gyin, which also has small bullae. 
My series was taken near the shores of the Inner Gulf of 
Sian from Islands in which (Koh Si Chang and Koh Phai) T have 
described the races R. 7, portus and R. 7, poenitentiari 2; both are con- 
sistently yellower and paler than the adjacent mainland animal, the 
underparts slightly more tinged with yellowish and the feet whiter ; 
the former island race is larger and the latter of about the same size 
as the mainland animal but with larger teeth and palatal foramina. 
( For measurements see table posted.) 
37. Rattus rattus lanensis, sub-p. 1 v. 
Specimens examined :—1 4,42 ad. and subad., 7 imm. and 
juv. examples from Koh Lan, Inner Gulf of Siam. 
Diagnosis. Colour consistent, about the same above as in 
the lighter, yellower individuals of the mainland, but white of under- 
parts slightly tinged with yellow. Size and skull about the same 
but teeth larger and palatal foramina extending further back- 
wards. Duller and darker than R, r. poenitentiari mihi, 
| Journ, N. HL. Soe, Siam, 11, p. 286 (1917). 
2 op. Git, iL, pp. 221,29 (1915). 
JOURN, NAT. HIST, SOC, STAM, 
