HOIV ANIMALS k'NOIV THINGS 



log 



toes have many hundreds of these long, fine antennal 

 hairs, and on the sounding of a tuning-fork they have 

 been observed to vibrate strongly. In the base of each 

 antenna there is a most elaborate organ, composed of fine 

 chitinous rods, and accompanying nerves and nerve-cells 



Fig. 74. — The auditory organ of a locust (Mclanoplus sp.). The large 

 clear part in the center of the figure is the thin tympanum, with the 

 auditory vesicle (small black pear-shaped spot) and auditory ganglion 

 {at left <jf vesicle and connected with it by a nerve) on its inner surface. 

 (Greatly magnified; photomicrograph by Geo. O. Mitchell.) 



whose function it is to take up and transmit through the 

 auditory nerve to the brain the stimuli received from the 

 external auditory hairs. 



Concerning the sense of sight and the seeing organs the 

 following brief discussion is taken from Jordan and Kel- 

 logg's "Animal Life " : 



"Not all animals have eyes. The moles, which live 

 underground, insects and other animals that live in caves, 

 and the deep-sea fishes which live in waters so deep that 



