516 



GA VI ^. 



LARID^. 



LARID^E. 



Hydrochelidon nigra (Linnoeus*). 



THE BLACK TERN. 



Sterna Jissipes. 



Hydrochelidon, Boief. — Bill about as long as the head, nearly straight, 

 tapering ; nasal groove rather long ; nostrils basal, direct, oblong. Wings long 

 and pointed, the first quill-feather the longest. Tail short, very slightly forked. 

 Legs short : tlie tibia bare for some distance ; the tarsus compressed, anteriorly 

 scutellate ; three toes in front connected by deeply scalloped webs ; hind toe 

 small and elevated ; claws long, slender, curved. 



The relationship of the order Gavi^ to the Limicol.e is 

 now generally, although somewhat tardily, admitted. The 

 Terns and Gulls comprised in the former order, show the 

 gradual modifications consequent upon a more or less aquatic 

 or pelagic existence, whilst, in an opposite direction, the 

 Waders have undergone modifications in accordance with 



* Sterna nigra, Linnteus, Sjst. Nat. Ed. 12, i. p. 227 (1766). 

 t Isis, 1822, p. 563. 



