THE BLACK TERN. 
277 
Adult, 9, 24. Young, in autumn, 71 ; wing, 9 T 8 2. 
Arrives in Texas from the south early in spring, proceeds along the coast 
to the Mississippi, then ascends that river and its tril utaries, breeding around 
ponds, or along the streams ; and even advances to the Fur Countries, where 
it also breeds. Abundant. Migratory. Occasionally along the cbasts of 
the Middle Atlantic Districts. 
Adult Male. 
Bill about the same length as the head, slender, tapering, compressed, 
nearly straight, very acute. Upper mandible with the dorsal line slightly 
arched, the ridge convex at the base, narrowed towards the end, the sides 
sloping at the base, slightly convex and nearly perpendicular towards the tip, 
the edges sharp, the tip acute. Nasal groove reaching nearly to the middle 
of the mandible ; nostrils basal, linear, direct, pervious. Lower mandible 
with the angle very narrow, acute, extending beyond the middle, the dorsal 
line straight, the sides erect and slightly convex, the edges sharp and slightly 
inflected, the tip extremely acute. 
Head of moderate size, oblong ; neck rather short ; body slender. Feet 
small ; tibia bare fof a short space ; tarsus very short, covered anteriorly with 
small scutella, laterally and behind with reticular scales ; toes very slender, 
the first extremely small, the third longest, the fourth nearly as long, the 
second much shorter, all scutellate above, the anterior connected by short 
reticulate webs, having a concave margin, and not extending much beyond 
the middle of the toes. Claws long, slender, arched, compressed, acute, that 
of hind toe smallest, of middle toe largest, and having a thin dilated inner 
edge. 
Plumage soft, close, blended, on the head short, on the back somewhat 
compact. Wings very long, narrow and pointed ; primary quills tapering, 
the outer slightly curved inwards at the end, the first longest, the rest rapidly 
graduated ; secondary short, broad, incurved, rounded. Tail of moderate 
length, emarginate, of twelve rounded feathers. 
Bill brownish-black. Iris brown. Feet reddish-brown, claws black. 
Head, neck, breast, sides, and abdomen, greyish-black ; lower tail-coverts 
white, lower wing-coverts bluish-grey. The general colour of the upper 
parts is dark bluish-grey ; the outer web of the first quill greyish-black. 
Length to end of tail 9 inches, to end of wings 11 ; extent of wings 24 ; 
wing from flexure 81 ; tail 3§ ; bill along the back lyV, along the edge of 
lower mandible lfV ; tarsus t a ; middle toe T 8 2 , its claw ft. Weight 3 oz. 
Young'Male in autumn. 
The bill, iris, and feet, nearly as in the adult. The upper parts are grey- 
ish-blue, the feathers of the fore part of the back, and especially the scapu- 
lars, brown towards the end ; the upper and hind part of the head greyish 
