32 MR. C. BODEN KLOSS ON 



amount of individual variation fi'om each localit}'. The only 

 difference I can detect is that, series for series, the Siamese 

 animals have perhaps a somevi^hat greater quantity of black hairs 

 on the forehead and top of head, but the distinction is un- 

 important, and I have therefore placed them under the name 

 first definitely applied to the crab-eating monkey of the S.E. 

 Asiatic mainland. 



It may be said that the blackish hands and feet which Elliot 

 (' Eeview of the Primates,' vol. ii. pp. 189, 230, 231, 233 (1913)) 

 emphasizes as the distinguishing characters of M. irtcs do not, 

 so far as my experience goes, exist. 



On the whole the series is very uniform, save that adult females 

 have no trace of rufous on the dorsal surface. 



We met with a large herd of these monkeys on the mainland 

 on one occasion while sailing up a river at daybreak, but were 

 not prepared for obtaining them. 



Measurements. — See table, p. 67. 



4. Peesbytis geemaini M.-E. 



SemnojntheGus germaini Milne-Edwards, Bull. Soc. Philom. 

 1876, Feb. 12; Flower, P. Z. S. 1900, p. 319; de Pousargues, 

 Mission Pavie, Indo-Chine, Etudes Diverses, iii. p. 517 (1904) 

 (mis-spelt germani). 



Presbytis germaini Gyldenstolpe, Arkiv for Zoologi, Stockholm, 

 Band 8, No. 23, p. 5 (1914). 



One adult male of this handsome silvery-black leaf-monkey was 

 obtained at Klong Yai, S.E. Siam, where, and in Cambodia and 

 Cochin-China, it is the representative of the cristata group. 



Measurements. — See table, p. 67 ; and also under P. g. man- 

 clibidaris. 



5. Presbytis germaini mandibularis, subsp. n. 



Type. Adult male (skin and skull). No. 1433/C.B.K. B.M. 

 No. 15.11.4.5. Collected on Koh Chang Id., S.E. Siam, 7th 

 December, 1914. 



Characters. — A form of P. germaini characterised by smaller 

 size, paler legs, more slender zygomata, broa,der interpterygoid 

 space and basioccipital, and by the higher and narrower ascending 

 ramvis of the mandible. 



Colour. — Resembles P. germaini, except that whereas in the 

 mainland animal the buttocks, outer and posterior sides of legs 

 are pure silvery white, sharply contrasting with the black feet 

 and back, in the island form these areas are black or greyish, 

 only frosted with silver, and thus less contrasting with the feet 

 and back. 



Shull and Teeth. — As compared with an adult but less aged 

 male from the mainland, the skull is smaller ; the zygomatic arches 

 much less deep (4 : 7 mm.), the lower edge being concave instead 

 of straight ; the basioccipital is relatively broader ; the inter- 

 pterygoid space broader and more oblique, the sides more spread 



