GREBES. 271 



DIVERS. 



There are about fourteen British, species, resident or visi- 

 tant, belonging to this division. The genera differ in their 

 capacity of flight, and the form of their bills, but they all 

 agree in the far backward position of the legs, the nearly 

 erect position which they must assume when they stand or 

 walk upon the ground, and the capacity of diving. Some of 

 them have the toes lobed like the coot, others have them 

 fully webbed. When they rest upon land, they generally do 

 so on the whole length of the tarsi, by which means they 

 obtain an extensive base, and the tightening of the tendons 

 over the tarsal joints the one way, and the tibial joints the 

 other, gives great firmness and stability. That mode of 

 standing is not very common among birds ; but many qua- 

 drupeds do it, and even man in the rude state with the joints 

 bent as a way of reposing, though in our common standing 

 or walking position the application of the foot to the ground 

 is the same. When the toes only are on the ground, these 

 birds balance themselves with difficulty. 



GREBES (Podiceps). 



This is a singular genus, having some resemblance to the 

 coot, yet differing in many of its characters. The bill is of 

 middle size, conical, pointed ; a little bent down at the tip of 

 the upper mandible, compressed in the whole of its length, 

 and hard and firm. The legs are placed far backwards and 

 of considerable length. The tarsal joints admitting of a 

 slight degree of oblique or rolling motion, the tarsi com- 

 pressed, with a margin on the thin edges, the toes much flat- 

 tened, connected at their bases by membrane, and with broad 

 scolloped margins. Tail altogether wanting. Wings short 



