PLUMAGE 485 



is of a somewhat elongated form, the neck long, the head 

 rather large. The breast-feathers are convex in shape, 

 which helps to break the shock of contact with the 

 water, while the hair-like texture of the neck-feathers 

 may be meant to facilitate gliding through it. The wings 

 are narrow for their exceptional length, the primary - 

 quills, ten in number, black, very stiff, and tapering to a 

 point. The bastard-wing is black, and below it there is 

 a patch of white about three inches long. The secondary - 

 quills or cubitals, twenty-six or -seven in number (for the 

 Gannet has a very long fore -arm — radius and ulna)* are 

 short, broad, rounded at the ends, and white in colour. t 

 The tail is graduated or cuneiform in shape, and consists 

 of twelve feathers with uncommonly stiff shafts, much 

 used in steering through the air. 



Authors agree that there is no difference in the sexes. 



The Bi-annual Moult.— The moult takes place in March, 

 April and May, and again in August or September; it 

 seemed to go on a long time in my tame Gannets, but Mr. 

 G. Bolam thinks it is only in full moult in the autumn. In 

 my birds, not only were the body-feathers shed, but also 



* See p. 33.5. 



t The cubital wing-coverts of Sula are figured in Mr. J. G. Goodchild's 

 article on this subject ("P.Z.S.," 1886, p. 199), where it is stated that in 

 style they most resemble those of Fregaia, Pnffmvs, and Diomedea. 



