vi FORM AND FUNCTION 119 



removed, one is struck with the smoothness of the 

 brain. 



The ol factor)- lobes (olf.), in which lies the sense of 

 smell, arc small cone-shaped objects which project 

 from underneath the front end of the hemispheres, 

 their smallness suggesting that birds depend little on 

 this sense. Formerly it was thought that vultures 

 " scented the carrion from afar," but Darwin showed 

 by experiment that this was not the case. He wrapped 

 some meat in paper, and put it near some condors 

 that were tethered in a garden. When it was only a 

 yard off him, an old cock bird " looked at it for a 

 moment with attention, but then regarded it no more." 1 

 It was pushed closer and closer till at last it touched 

 his beak, when the paper was " torn off with fury." 



The optic lobes (o.l.) are many times larger — two 

 rather egg-shaped bodies at. the sides of the brain, 

 partly below the hemispheres. Their size suggests, 

 what is really the case, that the vulture finds his food 

 by sight. His eyes sweep the whole country round 

 as he flies, and when he swoops down upon a carcass 

 he is seen by numbers of others who quickly follow. 



Towards the back of the brain between and under the 

 hemispheres lies a small oval object called the pineal 

 gland or body (pn.). What may now be its function, 

 if it has any, is unknown. Formerly it is believed to 

 'have been a central eye. In the bird's skull, in which 

 the fusion of bones is so marked a characteristic, we 

 should not expect to find an)- external evidence of 

 this rudimentary organ. But in lizards a hole in the 



1 Darwin's Journal of Researches, chap. ix. (p. 133, Minerva 

 ed.). 



