254 BLACK-BAKED TERN. 



neck, where it forms a white collar ; all the rest of 

 the upper plumage is of a very light pearl -grey or 

 cinereous; the quills are the same, glazed as it 

 were, over a deep black, which shows its full tint 

 on the inner webs of the five first primaries, these 

 feathers being entirely blackish, without the white 

 longitudinal stripe so general among the other terns ; 

 all the shafts are white both above and below. The 

 tail is forked,, and in this specimen is about two 

 inches and a half shorter than the wings; the 

 feathers, however, have obviously not reached their 

 full growth ; the outer pair, which seem to exhibit 

 the adult colour, are of the same very light tint as 

 the back, but darker towards their tips ; the others 

 are dark cinereous, mottled with white, indicating 

 immaturity; the bill is rich red, tipt with blackish, 

 and the feet, which are strong, are deep black ; the 

 middle claw is much curved outwards, and that of 

 the hinder toe is short and very straight. 



Total length, 21 inches ; bill, front, 2J ; gape, 3^ ; 

 wings, 15 1, being 2| longer than the tail; tarsus, 

 1 J ; bare space above the joint, ^ ; middle toe and 

 claw, 1 T 6 ; hind ditto, J. 



