THE GANNET'S ANATOMY 



537 



There is one aid which the Gannet has, which must be 

 a great protection every time it strikes the water, viz 

 a strong nictitating membrane. This membrane, which 

 springs as in other birds, from the corner of the eye nearest 

 to the beak, is moved by two muscles. It can be drawn 

 to and fro, and is evidently transparent, or partially so.* 



Besides this, the muscles around the eye must be very 

 powerful, for when handling a live Gannet, I have observed 

 them to expand and contract enough to raise the skin 

 perceptibly. 



The Brain. — Professor Newton has stated his opinion 

 that accurate weights and measurements of birds' brains 

 might help in deciding precedency in classification (" Dic- 

 tionary of Birds," Introd., p. 116), but at present this 

 central part of the nervous system has not been studied 



* A photograph of a Hving 

 Golden Eagle by Mr. Seton 

 Grordon, so well shows the 

 way in which the eye is 

 completely covered by this 

 membrane, that I am tempted 

 to reproduce it. For a proper 

 description of this organ 

 see Newton and Gadow's 

 "Dictionary of Birds," 

 p. 233. 



