PLUMAGE OF BIRDS. 235 



extremity of tlie feather^ are curved downward or toward the 

 internal surface of the shaft ; those which arise from the under side 

 of the barb are curved in the contrary direction : so that the two 

 adjoining series of hooked barbules lock into one another in a 

 manner which has been compared to the fastening of a latch of a 

 door into the catch of the door-post. There is much complicated 

 variety in the interlocking mechanism here generally explained. 



Besides the parts which constitute the perfect feather, there is 

 an appendage attached to the upper umbilicus, called the accessory 

 plume {]Ly2)orachis). It is usually a small downy tuft, but varies 

 both in diiferent species, and even in the feathers of different 

 parts of the body of the same bird. In the quill-feathers of the 

 wings and tail, it retains the state of a small tuft of down ; but in 

 the body-feathers of Hawks, Grouse, Ducks, Gulls, &c., it is to be 

 found of all sizes, sometimes equal to that of the feather from which 

 it is produced. 



In the Ostrich and Apteryx the feathers have no accessory 

 plume ; in the Rhea it is represented by a tuft of down ; in the 

 Emeu it rivals in size and structure the original feather ; and in 

 the Cassowary, besides the double feather, there is a second ac- 

 cessory plume, so that the quill supports three distinct shafts and 

 vanes. 



The feathers vary in form in different parts of the bird accord- 

 ing to their functions, and afford zoological characters for the dis- 

 tinction of species ; they have, therefore, received in Ornithology 

 distinct names. The ordinary imbricated feathers which cover the 

 body are called ^ clothing feathers :' the larger ones for special uses, 

 ' quill-feathers.' Those which surround or cover the external open- 

 ing of the ear are termed the * auriculars.' Those which lie above 

 the scapula and humerus are called the ^ scapulars.' The small 

 feathers which lie in several rows upon the bones of the anti- 

 brachium are called the * lesser coverts ' {tectrices primce). Those 

 which line the under or inner side of the wings are the ' under 

 coverts.' The feathers which lie immediately over the quill- 

 feathers are the ^ greater coverts ' (tectrices secundcE). The quill- 

 feathers supported by the wings are the ' remiges,^ or ^rowing- 

 feathers.' The largest of these remiges, which arise from the bones 

 of the hand, are termed the ' primaries ' (^primores). Those which 

 rise from the ulna, towards its distal end, are the ^secondaries' 

 {secundaricB). Those which are attached to its proximal extremity 

 are the ^ tertiaries ' {tertiarice). These in some Birds, as the Wood- 

 cock and Snipe, are so long as to give them the appearance, when 

 flying, of ha\dng four wings. The quill-feathers which grow 



