NIDIFICATION AND INCUBATION 357 



appearance of inflation when a Gannet is on its nest, and 

 a corresponding compression of plumage, I believe, when 

 it rises, which gives some colour to this idea, but nothing 

 else can be advanced, that I know of, in corroboration of 

 their being possessed of such a power. 



It was long ago stated by Martin,* and subsequently 

 proved by Mr. Booth, •}" that the male and female Gannet 

 take turns in sitting, and there is no proof of one doing 

 a larger share of incubating than the other. There are 

 some species of birds in which all the incubating is done by 

 the male, and probably very few in which that sex takes no 

 part whatever in it. 



In conclusion it may be convenient to mention the 

 principal plates of Gannets' eggs in works on Oology. 



Plates of the Egg. 



Hewitson. — " British Oology," plate xxxiv. (1836) ; " Eggs 



of British Birds," plate cxvi. (1845 ?) ; Ditto, 2nd 



edition, plate cxxx. (1856). 

 Thienemann. — " Systematische Darstellung der Fort- 



pflanzung der Vogel Europa's," Heft 5, p. 43 (1838) ; 



" Fortpflanzungeschichte der Ges. Vogel " Tab. xciii. 



(1856). 



* " Voyage to St. Kilda," p. 50. 

 t " Rough Notes," Vol. III. 



