BIRDS. 219 



ed the primaries. They extend from the tip to the first 

 obviously moveable joint. They differ in number, rela- 

 tive length, abbreviation of the web on one or both sides, 

 and in colour. The quills on the next joint towards the 

 base, are called the secondaries. These are usually shorter 

 and broader than the former. At the joint which sepa- 

 rates these two kinds of quill feathers^ there is a tuft of 

 three or four stiff feathers, constituting the wing-let or bas- 

 tard wing. The lertlarles are those which grow from the 

 humeral joint of the wing. The coverts, distinguished 

 into upper and under from their position on the wings, arc 

 placed in several rows, those feathers being the largest 

 which cover immediately the quills. The scapulars cover 

 the sides of the back, and are usually longer and more lax 

 than those of the neighbouring parts. The taiL-fcathci'S, 

 which are strong as those of the wing, have likewise their 

 upper and under coverts. Besides feathers, many birds 

 have hairs, particularly as whiskers or vibrissse. The oil- 

 bag' situated on the rump, has usually one opening, but in 

 the goose there are two ; the summit is surrounded by a 

 tuft of soft feathers *. Those places of the skin of birds 

 unprotected by feathers, likewise exhibit peculiar charac- 

 ters. The jaws are covered with the horny bill which, in 

 its various forms, furnishes important characters. At the 

 base of the bill, there is sometimes a naked skin, termed 

 cere., or, when it extends from the bill to the eye, lore. 

 The legs and toes are covered with scales which are closely 

 united with the skin, and appear either reticulated or plait- 

 ed. The soles of the feet are more or less rough, with tu- 

 bercles and papilla?. 



* In many birds, as the parrot, wood-pigeon, and heron, the feather;;, 

 especially those under the wing, are covered with a ?nft. mealy powder. 



