AUDITOEY APPARATUS. 



597 



two nearly spherical cavities (fig. 294, d), which in themselves repre- 

 sent the osseous labyrinth of the ears. A vesicle or membranous 



Fig. 294. 



Brain and auditory apparatus of the Cuttle-fish : a, 6, brain ; c, auditory apparatus ; 

 d, cavity in which it is lodged; e,f, g, the eye. 1, 2, 3, otolith. 



sacculus (c), likewise Fig. 295. 



nearly of a spherical 

 form, is suspended in 

 the centre of each of 

 these cartilaginous cells 

 by a great number of 

 filaments, that are pro- 

 bably minute vessels. 

 The two auditory nerves 

 derived from the euce- 

 phalon enter these ca- 

 vities through special 

 canals ; and each, divi- 

 ding into two or three 

 branches, spreads out 

 over the vesicle to which 

 it is destined. The au- 

 ditory vesicle itself is 

 filled with a transparent 

 glairy fluid, and con- 

 tains, attached to its 

 posterior part, a minute 

 otolith (1, 2, 3), of vari- 

 able shape in different 

 genera, the oscillations 

 of which doubtless in- 

 crease the impulses whereupon the production of sound depends. 



Generative organs of the female Cuttle-fish. (After Cuvier.) 



