26 



CORTIMH. 



A feature wliicli is also of some use in distiiiguisliing gco- 

 grapliical races is the colour of the bases of the feathers. In 

 southern birds these are nearly always very dark, in Central Indian 

 bii'ds they vary a great deal from pale dirty white to dark, whilst 

 in the northern mountain birds when fully adult they are 

 generally pale and often pure white. Andaman birds seem 

 iuvai-iably to have the bases to their feathers a very pure white, 

 and differ in this respect from, their nearest allies in Assam and 



Fig. 4. — Head of C. roronoidcs. 



Fig. 5. — Foot of C. coronoidcs. 



Burma, from which it may be found necessary to separate them ; 

 they agree with tliese, however, in their very heavy bills. 



As so much of the material for examination in museums is 

 unsesed, it has been very difficult to draw conclusions from 

 measurements. It must be remembered, however, that females 

 on the whole run smaller than males and certainly have smaller, 

 slighter bills. Although non-migratory birds and in their wilder 



