MAMMALS FROM SIAM. 29* 



line. All are covered with dense evergreen tropical forest, and 

 Koh Chang and Koh Mak alone are inhabited. 



The only terrestrial mammals on the smaller islands are forms, 

 of Epimys surifer and E. rattus. Koh Mehsi, though nearer the 

 mainland, higher, and in shallower water, has a form of the 

 latter only. 



Koh Chang and Koh Kut vary in the composition of their- 

 faunas, for while the former lacks a Ratufa, a species which 

 occurs on Koh Kut, the latter is without any Preshytis, Tujxiia, 

 or rattus rat, all of which are found on the larger island. On 

 both a form of Epimys jerdoni is very common, though it wa& 

 not met with on the mainland. 



When we got back to Bangkok visits were paid to Koh Si 

 and Koh Phai in the Inner Gulf, and accounts of the collections- 

 made on them and of the reptiles and batrachians obtained in 

 the south-east appear in the ' Journal ' of the Natural History 

 Society of Siam, while a report on the birds is contributed to 

 ' The ibis.' 



The first set of all collections has been given to the British 

 Museum (Nat. Hist.) at South Kensington, and the second tO' 

 the U.S. National Museum at Washington. 



Ridgway's colour-names used here are those of his second' 

 publication, ' Colour Standards and Nomenclature,' 1912 



Though in the title of this paper I have mentioned only one- 

 locality for the sake of brevity, it may be said that most of the 

 specimens obtained at Ok Yam and many from Klong Yai 

 actually came from the Cambodian side of the boundary, as it 

 now runs between Siam and that country. 



1. Hylobatbs pileatus Gray. 



Hylohates pileatus Gray, P. Z. S. 1861, p. 135, pi. xxi. ; de Pou- 

 sargues. Mission Pavie, Indo-Chine, Etudes Diverges, iii. p. 511 

 et seq. (1904). 



Hylohates agilis, Yeiviety pileatus Flower, P. Z. S. 1900, p, 313. 



5 adult males, 2 adult females, 1 female juv., from Klong 

 Menao and Len Ngop, S.E. Siam. 



It is probable that these animals are practically topotypes, as 

 Mouhot's specimens came from some part of Cambodia. The 

 statement that they were met with on a small island near the 

 coast must be received with hesitation until their occurrence in> 

 an insular locality is confirmed. 



The original description of the species applies excellently to- 

 the present series of this individually vai'iable genus. The five 

 males are (though paler on the dorsal region and the lower half 

 of the legs) black or brownish black throughout except for a ring 

 round the face, the hands and feet, and a genital tuft, which are 

 dull white or buffy-white. The pale band running fi*om the- 

 temples round the back of the head, greyish, ashy or brownish 

 posteriorly, is not always complete behind, and then the dark 



