228 STERNIN^E. 



ing from the egg, but, unless disturbed, remain some time 

 in the nest, or conceal themselves among the herbage or 

 stones. The males are little larger than the females, 

 and generally the sexes are coloured alike. The young 

 are differently coloured from the adult. 



FAMILY XLIX. STERNINJE. STERNINE 

 BIRDS, OR TERNS. 



Although the Terns or Sea- Swallows are closely allied 

 to the Tropic-Birds on the one hand, and to the Gulls on 

 the other, it seems expedient to keep them separate, as a 

 family, from the latter, as they generally differ so much 

 in form and habits as to be easily distinguishable. They 

 are all of small size, and remarkable for the extreme 

 buoyancy of their flight. The body is very slender ; the 

 neck of moderate length, or short. The head oblong, 

 and of moderate size. Bill about the length of the head, 

 rather slender, compressed, nearly straight, tapering to 

 a narrow point. Palate with three longitudinal ridges ; 

 tongue very slender, tapering, with the point slit ; oaso- 

 phagus extremely wide ; stomach moderate, muscular, 

 with roundish tendons, and dense, broadly rugous epi- 

 thelium ; intestine moderate, coeca small and cylindrical. 

 The trachea with a single pair of inferior laryngeal mus- 

 cles. Nostrils subbasal, linear, direct, pervious. Eyes 

 of moderate size. Apertures of ears rather large. Feet 

 very small ; tibia bare below ; tarsus very short, slender, 

 scutellate before ; toes very small, the first extremely so, 

 the fourth considerably shorter than the third ; the an- 

 terior toes with webs deeply concave at the margin ; 

 claws arched, compressed. Plumage soft, close, blended, 

 the feathers broad and rounded ; wings very long, nar- 

 row, pointed, the outer primaries slightly curved inwards; 

 tail long, of twelve feathers, forked, sometimes even, 

 rounded, or graduated. 



