660 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXIII.. 



however, in nearl}^ so great a contrast as they are in the further' 

 East, hence the differences in plumage are themselves less startling^ 



To the South the extension of horsfieldi appears to have been 

 very gradual, and the variations between the extremes of type, that 

 is to say, between the black Kalij in the North and the grey Silver- 

 Pheasant in the South-East, have in some areas become practically 

 constant and well-defined, and may, therefore, well rank as sub- 

 species. Thus we have cuvieri, a very dark bird with a small 

 amount of white vermiculation on the upper plumage, which acts 

 as a sort of buffer state between horsfieldi and other forms in the- 

 South and East which more nearly resemble the true Silver 

 Pheasants. This form extends from Arakan round in a rough, 

 horse-shoe to the North-West Shan Hills. 



South of this as the Hills get higher and drier in the South; 

 Arakan Yomas, we get a paler bird, which is very close to lineatus,. 

 but is darker, and still shows signs of the white banded rump typir- 

 cal of true horsfieldi. This form has been named oatesi by Ogilvie- 

 Grant, and is sufficiently constant in colouration throughout the 

 Southern Arakan Yomas to deserve sub-specific rank. East of the- 

 Irrawaddy Piver we get into a region of higher hills with, a smaller 

 rainfall than on the West, and accordingly we here come on a yet^ 

 paler form which has lost all trace of the barred rump, contrasting: 

 with the rest of the upper plumage. This is the true lineatus, and' 

 it is almost entirely confined to the Pegu Yomas running North and< 

 South between the Sittang and Irrawaddy Rivers. 



Extension further South seems to have practically stopped at thi-s- 

 point, and there then appears to have set in a new movement 

 extending North and East. 



That this extension in the East has not proceeded Southwards- 

 from the Himalayas simultaneously with that on the West is shewni 

 by the fact that the greatest contrast between any two forms is that 

 shown between nycthemerus and horsfieldi, which practically meet 

 one another in the extreme North-East of the Silver Pheasants' 

 habitat. Moreover, from the birds on the East we find that ail 

 trace of the barred rump so typical oi horsfieldihas been eliminated,, 

 whereas this feature exists in all birds down the West Coast, and 

 does not totally disappear until the true lineatus is reached. 



Another feature which would seem to prove that extension has 

 been South and then again North and East is shown by the fact 

 that hybrids are far more numerous on the extreme North-East, at 

 the point of contact between nycthemerus and horsfieldi than they 

 are anywhere else. Had extension commenced working down the 

 East, then hybrids would have disappeared in some intermediate- 

 form, or have become established as a definite sub-species. 



Working North and East, we find the amount of white still 

 gradually increasing in extent, until in the North we come to the- 



