﻿E. LÖNNBERG, NEW GUEREZA. 9 



2. Colohus angolensis cottoni Lydekker 1905. 



3. Colohus angolensis sandhergi Lönnberg 1908. 



5. Colobus palliatus Peters 1868. 



6. Colobus palliatus sharpei (Thomas) 1902, 



7. Colobus ruwenzorii Thomas 1901. 



8. Colobus abyssinicus (Oken) 1816. 



9. Colobus abyssinicus occidentalis (Rochebrune) 1887., 



10. Colobus abyssinicus gallarum (Neumann) 1902. 



11. Colobus abyssinicus matschiei Neumann 1899. 



12. Colobus abyssinicus poliurus Thomas 1900. 



13. Colobus abyssinicus caudatus Thomas 1885. 



14. Colobus abyssinicus vellerosus Is. Geopfroy 1830. 



15. Colobus ursinus (Pennant) Ogilby 1835. 



16. Colobus polycomos ? Illiger 1811. 



The approximate habitat of these different forms is elu- 

 cidated on the accompanying sketch - map (fig. 3) by their, 

 corresponding numbers from the Hst above. 



A couple of years ago Lvdekker pubHshed a paper (15) 

 on the »Colour Evolution in Guereza Monkeys». In this he 

 draws attention to the fact that these monkeys exhibita 

 very interesting series from the black C. satanas to the white- 

 mantled, whitetailed C. a. caudatus. This series has now 

 been suplemented with one intermediate link more. 



Referring to the fact ascertained by several travelling 

 naturalists that »in the case of the white-tailed species the 

 excessive length of the white hair forming the mantle and 

 the tailfringe appears to have been evolved in order to ren- 

 der the creature as inconspicuous as possible amid the long 

 pendent greyish-white lichens which clothe the branches of 

 the trees of an East African forest» {15), Lydekker says 

 »the evolution of such a type is, of course, easy to compre- 

 hend». But then he adds: »as in so many other cases, the 

 difficulty comes in with regard to the purpose of the colo- 

 ration in the intermediate types connecting this species with 

 the Black Guereza». Finally he questions: »What purpose 

 do these incipient attemps at the development of a pied coat 

 serve?» It appears to the present author that these »inci- 

 pient attempts» are just as easily understood and explained 

 but not as adaptations aquired for a protective resemblance 

 to the surroundings, but as serving for ornamental pur- 



BF 



