ORGAN OF HEARING IN FISHES. 



345 



229 



side by a small orifice with two subspherical ' atria,' on the body 

 of the atlas, close to the 

 foramen magnum, which 

 ' atria ' are supported ex- 

 ternally by the ossicles / 

 and m, and, by means of 

 the large ossicle o, are 

 brought into communica- 

 tion with the fore part of 

 the air-bladder, p. Both 

 the atria and common 

 sinus are filled by the 

 endolymph, and from the 

 fore part of the sinus a 

 1 canalis furcatus,' ib. i, 

 is produced, the blind 

 ends of which penetrate 

 the alisphenoids. In the 

 grovelling Loach (Colitis 

 barbatala), the air-bladder 

 would seem to exist 

 chiefly in subserviency 

 to the oman of hearino-. 

 It is so small as to be 

 wholly included within 

 the singularly modified 

 parapophyses of the se- 

 cond and third cervical 

 vertebras, which are ex- 

 panded and coalesced so 

 as to form a large ' bulla 

 ossea ' beneath their cen- 

 trums. 1 The three ossicles 

 on each side, which bring 

 the air-bladder into com- 

 munication with the ' atria' 

 of the labyrinth, are also 

 concealed by the fore part 

 of the parapophysial bul- 

 la3 : it is plain, therefore, 

 that they are not dis- 

 memberments of those 0l 'S an of Hearing in situ, with air-Madder and ossicles, Carp. 



LXXIII. 



1 xxxix. i. p. 380. 



