360 THE GANNET 



by a web is plainly visible in the folded foot, which is seen 

 resting upon the head. Numerous filaments of down can be 

 detected covering the body of the embryo in regular rows. 

 When at length the embryo has become a fully formed 

 Gannet-chick, it inhales air into its lungs, and breaks the 

 shell — the walls of which have been growing weaker — by 

 means of a hard scale, or " egg-tooth," as it has been 

 termed, at the end of its beak. According to Mr. T. C. 

 Walker's observations, the old Gannet sometimes assists in 

 the operation,* but of this I have no other evidence, and 

 think it requires confirmation. 



The Gannefs mode of Incubation. — On my first visit to 

 the Bass Rock, which was in 1876, one of the men surprised 

 me by saying that the Gannet incubated her single egg by 

 covering it with her large webbed feet. I was not then 

 aware that this singular habit had been placed on 

 record in the sixteenth century by Conrad Gesner,t 

 though subsequently it was discredited by less informed 

 writers, and disbelieved. It takes men a long time to put 

 aside prejudice and preconceived ideas when investigating 

 the habits of birds. By good fortune I was destined 



* " Zoologist," 1868, p. 1.366. It is certainly by the unaided efforts 

 of the nestling in most species that liberation takes place, but Mr. H. F. 

 Witherby has seen a domestic Fowl peck at the egg, as if helping the 

 chick ovit. 



■j- And also noticed by Svvave. 



