482 NATATORES. LARUS. 



black, with a slight tinge of red. Tarsi one inch and 

 three quarters long. 



Summer In summer, the forehead, crown, and back part of the 

 neck are deep black. In other respects there is no 

 striking difference between that and the winter plumage. 



GENUS LARUS, LINN. GULL. 



GENERIC CHARACTERS. 



BILL of mean length, strong, strait, cultrated ; the upper 

 mandible having the tip incurved ; symphasis of the lower 

 mandible strongly angulated, and ascending from thence to 

 the point. Nostrils placed in the middle of the bill, lateral, 

 oblong, narrow, and pervious. Tongue pointed, with the 

 extreme tip cloven. Wings long, acuminate. Tail even, or 

 slightly forked. 



Legs placed near the centre or equilibrium of the body, of 

 mean length and strength, with the lower part of the tibiae 

 naked. Feet of four toes, three before and one behind ; the 

 three front toes united by a membrane ; the hind one short 

 and free, articulated upon the back part of the tarsus. Nails 

 slightly falcate. Tarsi and upper part of the toes scutel- 

 lated. 



The passage from the Terns to the larger and more typi- 

 cal Gulls, is effected by certain small species of the latter 

 genus, possessing a less robust bill, and slightly forked tail. 

 In their changes of plumage also, they shew their connexion 

 with the former birds, by the head becoming entirely or partly 

 of a dark colour, as the season of reproduction approaches, and 

 being more or less white during the rest of the year. In the 

 larger Gulls the reverse takes place, the head and neck being 

 of an unsullied white during the summer, and in winter being 



