MAMMALS COLLECTED IN SIAM. 381 
Mus. XIII, p. 7) but it is of so unsatisfactory a nature that it 
would be unwise to make any remarks about examples from other 
localities before good topotypes have been obtained. Gyldenstolple 
states that specimens from Koh Lak are absolutely similar to true 
Rattus concolor from the Malay Peninsula, but the latter are not 
necessarily typical and a specimen from Tioman Island, Pahang, 
doubtless derived from the mainland or Singapore, has been named 
pullus by Miller. 
The measurements of my largest specimen are (No, 2235, 
3):—Head and body, 123; tail, 155; hindfoot, s.u., 25; ear, 16. 
Skull:—greatest length, 31; condylo-basilar length, 27; diastema, 
8; upper molar row (alveoli), 5.4; length of palatal foramina, 5.9; 
median length of nasals, 11; combined breadth of nasals 3.3; 
zygomatic breadth, 15 mm. 
I take this opportunity t> make a few remarks about 
Gyldenstolpe’s recently described form Rattus sakaratensis from 
Eastern Siam (tom. cit., p. 46, pl. VI, figs 6 and 9) erroneously said 
to be related to R concolor with which, and with R. concolor 
ephippiwm, it has been compared, It is obviously a member of the 
“jerdoni” group and if nothing nearer was available should have 
been referred to whiteheadi of which the author possessed 
examples from Borneo and from the Malay Peninsula (“asper” 
Miller). he figures of the skull agree exactly with skulls of these 
Malaysian animals but there are differences as regards the pelage, 
Amongst these the tail is said to be “blackish brown throughout 
and clothed with short hairs”; the only species of “jerdoni” rat 
known t) me with the former character is cremoriventer ; that is, 
however, a much larger animal with a longer, narrower skull and 
the tail is much longer than the head and body and almost 
pencillate ; the spines are extremely numerous and strong while in 
sakaratensis they are few and feeble; though the skull and dimen- 
sions are those of whiteheadi (asper) the colour is rather that of 
eremoriventer, 
VOL. III; NO.-4, 1919. 
