758 
SYSTEMA TIC SYNOPSIS. — LONGIPENNES — GA VI^. 
Tibiae bare about 0.75 ; tarsus 1.75, rather exceeding middle toe and claw, the scutella iu 
front replaced by polygonal scales similar to but larger than those on its sides, which are 
rough ; hind toe extremely small ; outer lateral nearly as long as middle toe and claw, which 
is 1.65. Bill dark vermilion red, growing lighter and somewhat ' Miaphanous " toM^ard the 
tip. Pileum and occipital crest glossy greenish-black, extending to below the lower level of 
the eyes, and occupying the termination of the feathers on the side of the mandible to the 
Fig. 512. — Caspian Tern, | nat. size. {From Brehm.) 
exclusion of the white ; lower eyelid white, forming a noticeable spot on the greenish ; a 
white streak along sides of upper mandible, not extending to the end of the feathers. Mantle 
pearl-blue, the line of demarcation between it and the white rather indefinite, both on nape 
and rump ; most of the tail-feathers, and especially the central ones, retaining a more or less 
pearly tint. Shafts of the primaries yellowish -white ] primaries grayish-black, but, when 
new, so heavily silvered over as to appear of a light hoary gray, especially on their superior 
aspects. On the inner web of all there is a central light field ; this is very narrow, even on 
the first primary, although it runs for some considerable distance, and on the others it rapidly 
grows less ; and it has no trenchant line of division on any of the primaries from the darker 
portions of the feather. Whole inner web of secondaries pure white, outer pearl-blue. Legs 
and feet black. Adult, winter plumage : Chiefly distinguished by a diminution in the bright- 
ness of the bill, and by a change in the character of the pileum. The vermilion is replaced 
by light orange-red, growing still yellower toward the tip of the bill and along the toraia. 
