234 
Genus II. — STERNA, Linn. TERN. 
Bill longer than the head, rather stout or slender, nearly straight, com- 
pressed, very acute ; upper mandible with the dorsal line slightly arched, the 
ridge rather broad and convex at the base, gradually narrowed toward the 
end, sides convex, edges sharp and direct, tip acute ; nasal groove short ; 
lower mandible with the angle very narrow, acute, extending to the middle, 
the dorsal line straight, the sides slightly convex, nearly erect, the sharp 
edges inflected, the tips very acute. Nostrils basal, lateral, linear, direct. 
Head rather large, oblong ; neck of moderate length and thick ; body slender. 
Feet short, moderately stout ; tibia bare for a considerable space; tarsus short, 
roundish, covered all round with small scales ; first toe very small, third 
longest, fourth a little shorter ; anterior toes connected by emarginate webs. 
Claws slightly curved, compressed, acute. Plumage soft, close, blended, 
rather compact on the back and wings. Wings extremely long, narrow, and 
pointed, the first quill longest, the rest rapidly graduated. Tail long, gene- 
rally forked, of twelvg feathers. Tongue very slender, tapering, with the 
point slit ; oesophagus extremely wide ; proventricular belt complete ; sto- 
mach rather small, moderately muscular, with the epithelium dense and lon- 
gitudinally rugous ; intestine of moderate length, rather narrow; coeca small. 
