ME. E. T. HIGGINS ON THE OTOLITES OF PISH. 159 



out for an instant doubting that fisK possess, in an exquisite 

 degree, the sense of hearing, i. e. of receiving the vibrations con- 

 veyed through the water, I must differ in opinion from Pliny and 

 all subsequent writers who speak of fish " coming when they are 

 called," of their being "assembled by means of music or of a 

 whistle," for one reason: "Sonorous vibrations taking place in 

 the air are with difficulty communicated to the water, unless a 

 membrane be interposed." And yet, in the above-cited cases no 

 artificial tympanum having been interposed, we are called upon 

 to believe that fish perceive and recognize the various modula- 

 tions of sound taking place in the air. May we not rather ex- 

 plain their assembling at any one spot by the vibrations commu- 

 nicated through the earth to the water giving them notice of the 

 approach of some person to the spot where they are accustomed 

 to be fed ? It is a fact well known to all observant anglers, that, 

 provided they keep out of sight and remain still, all the talking, 

 whistling, and shouting will not disturb the fish one hundredth 

 part as much as one stamp of the foot or sight of the person. 



There exists considerable modification in the form of the au- 

 ditory apparatus in the various families of fish ; and the passage 

 from the " single tubiform labyrinth of the Myxine," through the 

 " two semicircular canals and vestibule of the Lamprey," into the 

 tJiree semicircular canals and vestibule of the higher cartilaginous 

 and the whole of the osseous fishes is very simple. 



The vestibule has been described as " dilating into one or more 

 sacculi, separated from the alveus communis by a constriction or 

 narrow canal." This description may apply to a few fish ; but in 

 by far the larger number no such separation exists. I shall 

 therefore speak of the whole as the vestibule or vestibular sac, 

 connected by one, two, three, or more tubular prolongations with 

 the semicircular canals, the whole being filled with a thick muci- 

 laginous or oleaginous fluid called endolymph, and surrounded by 

 a thinner fluid, perilymph. " The semicircular canals are anterior, 

 posterior, and external," and, though of large size, are considerably 

 smaller than the passages traversed by them, and are suspended in 

 them by a delicate network of fine threads of cellular membrane, 

 no doubt for the purpose of softening the shocks received through 

 the walls of the skull. 



" In the higher Plagiostomata (Sharks and Eays) and in the 

 Sturgeon, and also in the Lepidosiren, the whole are imbedded in 

 thoM^aUs of the cranium," whdst in the osseous fish these internal 

 parts of the auditory apparatus are lodged in a depression of the 



