LARID^ — STERNIN^ : TERNS. 
761 
Tomia of both mandibles sharp and much inflected. Nasal groove long, fully half the culmen, 
narrow, not deep, directed obliquely downward and forward toward the tomia. A few oblique 
indistinct striae on both mandibles. The outline of the feathers on the bill is as usual. Adult in 
summer : Bill bright red, salmon-colored toward tip. Feet black ; soles and under surfaces of 
claws slightly yellowish. Crown of head, including long-flowing occipital crest, pure black, 
reaching down on the sides of the head to a straight line just on a level with the lower border 
of the eye ; the white of the cheeks accompanying the black to the foremost point of extension 
of the feathers in the nasal fossae. All the under parts rosy-white, with satin gloss. Tail 
entirely pure white, longer and more deeply forked than in winter. Back and wings pale pearl- 
blue; the usual pattern of coloration of the primaries. ''Length 19; extent 48" (label); 
culmen 2.75 ; gape nearly 4.50 ; depth of bill at base 0.50; gonys 1.50, not shorter than man- 
dibular rami; wing 12.25; tail 7-50; depth of fork 3.50; tarsus 1.25; middle toe and claw 
the same, or rather less. In winter : Bill orange, fading to yellow at tip and along cutting 
edges. Forehead and feathers on side of bill entirely white ; crown varied with dark and white, 
black prevailing on hind head, complete on the occipital crest and sides of head to eyes. No 
pink blush of under parts. Tail shorter than in summer, 5.00 or less, forked only about 2.00, 
washed over with pearly-blue. Total length less, owing to less development of tail, IG.OO- 
17.00. Young not seen. A truly elegant species, resembling the royal tern, but easily dis- 
tinguished. S. and C. Am. to California; unknown on our Gulf or Atlantic coast. 
S. (T.) canti'aca. (Of Kent, England. Fig. 515.) Sandwich Tern. Ducal Tern. Bill 
much longer than head, exceeding the tarsus, middle toe, and claw together; quite slender 
and attenuated for this sub- 
genus, tip excessively acute ; 
convexity of culmen, from 
tip to base, regular, but 
slight ; commissure gradual- 
ly declinato-convex through- 
out ; outline of mandibular 
crura decidedly concave ; that . 
of gonys about straight; 
eminentia symphysis hardly ' 
appreciable. Adult, breed- 
ing plumage : Bill black, ~ Sandwich Tern, nat. size. (Ad nat. del. E. C.) 
the tip for i to f of an inch bright yellow, sharply defined against the black; inside of 
mouth deep blue." Feet dull black. Pileum and occipital crest glossy black, with a tinge of 
green; the color extending just below the eyes, but leaving a space along the side of the 
mandible white to the extremity of the feathers. Mantle exceedingly light pearl-blue, fading 
on the rump and upper tail-coverts into pure white; but the rectrices themselves have a 
slight shade of pearly-bluish. Primaries colored as in maxima. On the inner web of the 
first the black space is broad and deep in color ; when about li inches from the apex of the 
quill it quite suddenly grows wider, so as to exclude the white portion from the tip altogether. 
The second, third, and fourth primaries have the same general pattern, but the white runs 
up further on the central portion than on the edge of the web, so that toward its end it 
receives a narrow edging of blackish. The other primaries have no blackish, but are simply 
pearl-blue, with broad M^hite margins along the whole length of their inner webs. The outer 
primaries are all heavily silvered when the quills are new. Dimensions of the adult : length 
15.00-16.00 inches; extent 34.00; wing from the carpus 12.50; tail 6.00; depth of emargi- 
nation 2.35 ; bill along culmen 2.25 ; along gape 3.00 ; its height at base 0.48 ; width, ditto, 
0.37; length of rami from feathers on side of lower mandible 1.00; gonys 1.20 (longer than 
rami); tarsus LOO; middle toe and claw, slightly longer. Adult, winter plumage: Yellow 
