346 NATATORES. FULIGULA. 



the laminated plates are larger and coarser, and entirely 

 concealed by the margins of the mandibles. In general form 

 they are also much shorter, thicker, and more depressed; 

 and the backward situation of the legs, with the great size 

 of their feet, make them move awkwardly and badly on 

 and . They swim well, though apparently deep in the wa- 

 ter, from their flattened shape ; and they are excellent divers. 

 It is in this latter mode, indeed, they obtain the chief part 

 of their food, consisting of aquatic plants and their roots, a s 

 well as mollusca and worms. They inhabit the rivers and 

 lakes of the interior of the country, and some of them are 

 occasionally found on the sea-coasts. The tracheal organi- 

 zation of the whole genus is upon one uniform plan, and the 

 differences are only such as might naturally be expected in 

 distinct species. The lower extremity or labyrinth consists 

 of a bony box, or, as it is called, Oraz, formed by the en- 

 largement and ossification of the lower larynx; from the 

 bottom of which the right bronchial tube issues. On the 

 left side of the orca, and attached to it, is a large orbicular 

 compressed chamber, called the Tympanum or Drum, formed 

 by a bony arch, more or less covered by a thin membrane ; 

 and to the base of this the left bronchial tube is attached. 

 The flight of the members of this genus is rapid, and sus- 

 tained by quick strokes of the wings ; and is often at a great 

 elevation in the air. Their colours are generally plain, and 

 not possessing much variety; and none of them have the 

 metallic lustre on the secondary quills that distinguishes 

 most of the Anatm^ which in them has been appropriately 

 termed the Beauty Spot, or Speculum. They are natives of 

 the Arctic Regions, passing the summer in very high lati- 

 tudes; and in the winter their equatorial migrations are 

 more or less extended according to the severity of the season. 

 Their flesh is tender and palatable ; in some species of fine 

 flavour, as in Fuligula Vallisneria, from North America. 



