62R 



STERNA. TERN. 



The Terns properly so called may be described as being 

 of a very slender, elongated form, with the neck short or of 

 moderate length ; the head oblong. The bill about the same 

 length as the head, nearly straight, compressed, tapering, 

 finely pointed ; the upper mandible Avith the dorsal line 

 slightly arched, the lower with the junction of the crura 

 medial, the dorsal line straight ; the edges of both sharp, and 

 the tips extended into very slender points. 



The tongue slender, tapering, horny, and slit at the point. 

 The oesophagus very wide ; the stomach muscular, with a 

 dense rugous epitheUum; the intestine of moderate length 

 and width, with small cceca, and a large cloaca. 



Nostrils sub-basal, linear-oblong, direct, pervious. Eyes 

 of moderate size. Apertures of ears moderate. Feet very 

 small ; tibia bare below ; tarsus very short, scutellate ; toes 

 small, slender, the first very diminutive, the third longest ; 

 interdigital membranes emarginate ; claws arched, com- 

 pressed, acute, that of the third toe proportionally large. 



Plumage mostly blended ; the feathers broad and rounded. 

 Wings very long, narrow, with long tapering ])rimaries, the 

 outer longest. Tail of moderate length, or long, forked of 

 twelve feathers. 



These birds are all of small size, and remarkable for the 

 elegance of their form, and their buoyant, gliding fiighl. 

 They are generally white beneath, pale bluish-grey on the 

 back, with the upper part of the head black. The occipital 

 feathers elongated. The young are mottled with brown. 

 Several of the recently proposed genera are included in this. 



