13 Auditory Aperttires in Quadrupeds and Birds, 



but, on the contrary, is expanded principally from behind, in 

 a forward direction, into nearly a circular aperture. This 

 opening is very well adapted, when the head is thrown late- 

 rally and upwards, for receiving sounds from above. His 

 prey is usually met with in hen-roosts, or perched on trees ; 

 and his mode of taking them by surprise induces him to ap- 

 proach them stealthily. Hence arises the necessity of sounds 

 indicating their immediate presence being transmitted to the 

 sensorium as soon as possible. The moment his ear indicates 

 his prey above him, his eye is immediately turned in that direc- 

 tion ; and thus, if within his reach, is very speedily captured. 

 What more beautiful provision for this animal's necessities 

 could be met with than those with which he appears to be pro- 

 vided? His ears first give the indication of the presence of his 

 prey, and his eye instantly contemplates the object of his pursuit. 

 Hitherto I have not been able to meet with any animal 

 whose auditory structure is the opposite to that of the fox, 

 viz. one where the outward ear is expanded into a nearly cir- 

 cular form, but arched, and overhanging from above down- 

 wards : hence I am compelled to look into the class of birds ; 

 and here an instance immediately offers itself in the owl genus, 

 where the above-mentioned structure is very well defined. 

 This formation, by a little observation, we find to be exceed- 

 ingly valuable to this bird : indeed, wanting it, he could 

 scarcely procure food sufficient for supporting his existence. 

 He never hunts or goes abroad for food except in twilight; 

 and even then, when in an old building where his prey 

 abounds, he will be seen perched majestically and silently 

 upon any projecting substance whatever. Thus elevated 

 above the ground, sounds indicating his prey must ascend, 

 and are received by the arched, overhanging, and concave 

 external bony structure of his ear. {Jig, 6. a) This function 



being roused, his head is 

 naturally turned into the 

 direction whence the sounds 

 emanate ; and he is thus 

 enabled to discover, if not 

 always to seize, his prey. 

 Here it may be proper to 

 remark, that the owPs eyes 

 are immovable in their sockets ; but that the very extensive 

 motion of its head upon the spine enables the object to be 

 seen in any direction, wherever its other faculties indicate. 



Having thus briefly pointed out examples of different struc- 

 ture in the organ of hearing, and alluded also to some of their 

 habits where the utility of such structure is valuable, not only 

 to animal preservation but also to subsistence, I shall now beg 



