VI 



FORM AND FUNCTION 1 53 



most secondaries, spring from the ulna or the humerus, 

 The name tertiaries for the latter has now been disused. 

 The total number of the remiges varies very much, the 

 Humming-bird having only sixteen, and the Albatross 

 up to fifty, the variation being found in the secondaries 

 much more than in the primaries. Covering the bases 

 of the remiges are the wing-coverts. The great flight- 

 feathers are not originally the hindmost ; by their 

 enormous development, they push the two rearmost 

 rows to the lower face of the wing, where, to show 

 their origin, they still carry the after-shaft undermost. 

 The large tail feathers are called rectrices or steerers. 

 They always make an even number, but may be as 

 few as eight, or, it is said, as many as twenty-four. Some- 

 where about twelve is the normal. Sometimes they are 

 useful in distinguishing species. Thus the Common 

 Cormorant has fourteen, the Shag only twelve. Shielding 

 the bases of the tail feathers are the tail-coverts. In 

 the same way we speak of neck-coverts and ear- 

 coverts. 



Though feathers are to a great extent dead things, 

 they are in connection with the living parts of the 

 body and, so, are frequently moved. Pelicans maybe 

 seen raising their feathers to dry them after a swim. 

 An old Hen with chickens raises them in anger. The 

 Long-eared Owl lifts his great "ears" to inspire 

 terror ; the Cockatoo raises his top-knot to add to his 

 dignity; the Peacock in pride of heart spreads his plumes 

 or rattles his quills. The behaviour of the Turkey- 

 cock is easy to interpret. 



To make these movements, there are distributed 

 generally muscles which move the skin and with it 



