STERNIN^E. STERNA. 229 



The Terns, not inaptly compared to Swallows, are re- 

 markable for their gliding, hovering, desultory, wavering, 

 and buoyant flight, their screaming- cries, social disposi- 

 tion, and irritable temperament. They deposit on the 

 bare sand their light-coloured and darkly-spotted eggs, de- 

 fend them and their young with pertinacity ; feed on small 

 fishes, Crustacea, and insects, which they procure by ho- 

 vering over the water, and dipping into it. They walk 

 very awkwardly on account of the shortness of their feet. 

 The plumage of the sexes is alike, but the young are 

 mottled, and do not acquire their permanent colours until 

 the third year. 



GENUS CXLVI. STERNA. TERN. 



Some Terns have the bill stronger than others, as might 

 be expected in an extensive genus, yet without presenting 

 characters by which they might with propriety be generically 

 distinguished. They are all of small size, with the body 

 slender, the neck rather short, the head ovate. Bill about 

 the same length as the head, nearly straight, tapering, finely 

 pointed ; upper mandible with the dorsal line slightly arched, 

 the sides sloping, the edges sharp and inflected, the tip very 

 slender ; the nasal groove rather long, with a faint ridge 

 and groove extending obliquely to the edge ; lower mandible 

 with the angle very narrow, the dorsal line straight, the sides 

 convex, the edges sharp, the tip very acute. Palate with 

 three longitudinal ridges ; tongue slender, tapering, papil- 

 late at the base, horny and slit at the point ; oesophagus 

 very wide and thin ; stomach muscular, with round tendons, 

 and dense prominently rugous epithelium ; intestine of mo- 

 derate length and width ; cceca very small, .cylindrical. 

 Nostrils basal, oblong, direct, pervious. Eyes of moderate 

 size. Apertures of ears moderate, *Feet small ; tibia bare 

 below ; tarsus very short, compressed, anteriorly scutellate ; 

 toes sma'l, slender, the first extremely small, the third 

 longest, all scutellate, the anterior connected by reticulated 

 webs, of which the inner is more deeply emarginate ; claws 

 arched, compressed, slender. Plumage close, blended, very 



