214 



(examples : Big Tainbelan, 101,651, paratype ; Perlieiitiau, 11.1.30.2 

 and 2,050 ; Great Redang, 2,059). 



From tliis darkest extreme the colour variations go in three 

 directions : (1) the light greyish element is increased and the blackish 

 or seal-brown more and more suppressed in the same proportion ; or 

 (2) the blackish or seal-brown element is lightened into paler tinges 

 of brown ; or (3) both changes are combined. 



By increase of the light grey (silvery grey, white-grey) and corres- 

 ponding decrease of the blackish (seal-brown) element the general 

 colour of the back is transformed into dark brown heavily mixed with 

 light grey (Tioman, 8.1.25.2 ; Perhentian, 11.1.30.1 and 2,047 ; Great 

 Redang, 2,057 and 2,060) ; into light mouse-grey (Tioman, 8.2.25.2 ; 

 Great Redang, 11.1.30.5) ; and from this through various intermediate 

 stages into the lightest extreme, in which the colour of the back may 

 be roughly described as light grey (silvery grey, white-grey, sometimes 

 with a wash of buffy) more or less thinly sprinkled with blackish (Big 

 Tambelan, 101,649, paratype ; Great Redang 11.1.30.7). The modifi- 

 cations take place by the seal-brown or blackish brown hairs being 

 gradually to a greater and greater extent replaced by * light grey 

 hairs. The darkest-backed and lightest-backed specimens are so 

 strikingly different in appearance that, if these only were known and 

 if they happened to have been obtained in different islands,- few 

 zoologists would hesitate to consider them distinct species. 



Either independent of this gradual spreading of the light greyish 

 element, or, on the contrary, combined with same takes place, in some 

 specimens, a gradual lightening of the blackish or seal-brown element 

 itself. By this change the general colour of the back becomes some 

 tinge of dark brownish (between seal-brown and vandyck-brown) more 

 or less heavily mixed with grey (Perhentian, 11.1.30.1 and 3, 2,048); 

 or, by increase and further lightening of the greyish element, mouse- 

 grey or pale grey more or less strongly washed with vandyck brown. 

 Prout's brown, or mars-brown. 



(Big Tambelan, 101,650, paratype; Aor, 112,404; Great Redang, 

 11.1.30.6 and 2,058). Finally, the mars-brown tinge may spread 

 over nearly the whole of the back, rendering the general colour light 

 mars-bro-wTa sprinkled with greyish (Lantinga, 2,051). 



COLOUR OF UNDER-PARTS. 

 The palest extreme is represented by specimens with the whole of 

 the breast and belly dark cinnamon-rufous (palest, more golden, in the 



* It is perhaps not unnecessary to say that, -whether the same iiidivichial 

 exhibits, during its life-time, various stages of liglitening of the coloxu- of the baek^ 

 or wliether the colour once acquired is preserved essentially unmodified during the 

 life-time of the individual, is entirely unknown. When it is said above that the 

 blackish hairs are gradually "replaced by " light grey, it only means that, passing 

 from the darkest through many intermediate stages to the lightest specimens, it 

 is quite evident that the colom- of the latter is produced by a gradual increase of 

 the greyish and corresponding decrease of the bkckish elements. 



