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Tor Ear AND HEARING OF THE BLIND-FISHES.* By Cart H. EIGENMANN 
AND ALBERT C. YODER. 
The following words of Prof. Cope are frequently quoted: “They 
(Amblyopsis) are unconscious of the presence of an enemy, except through 
the medium of hearing. This sense, however, is evidently very acute; for 
at any noise they turn suddenly downward and hide beneath stones, etc., 
on the bottom.” 
Miss Hoppin (Garman, 1889) was the first to cast doubt on this state- 
ment. She failed to get any response from Troglichthys as long as noises 
only were resorted to. 
Our own observations (Proc. Brit. Ass. A. Science, Toronto Meeting) 
on Amblyopsis confirm those of Miss Hoppin on Troglichthys. No noises 
produced had any effect on Amblyopsis. Whistles, tuning forks, clapping 
of hands, shouting in the reverberating caves, were alike disregarded. 
Not one observation was made that would indicate that these fishes can 
hear. This does not imply that the auditory organs of this fish are not 
fully developed. Nor is it an indication that the auditory function of this 
fish is degenerate, for Kreidl and Lee have both shown that fishes as a 
class are unable to hear. Kreidl’s observations were made on fishes which 
were blinded or from which the operator was hidden by some contrivance. 
Neither of these devices need be resorted to with the present species. 
Anatomically considered, the ear of Amblyopsis is normal. Numbers 
of ears together with the brains have been dissected out. These were 
treated either with Flemming’s strong solution or with Hermann’s fluid, 
either of which stained the nerve matter black. 
In the first place, the three semi-circular canals are present and each 
has its ampulla fully developed. The three ampullz and the sinus utricu 
lus superior communicate with the utriculus in front, behind, and above 
Below, the utriculus communicates with the sacculus, which terminates 
posteriorly in an appendage, the lagena. 
The three ear bones are present, one in the recessus utriculi, one (the 
largest) in the sacculus, and the other in the lagena. 
The auditory nerve divides into two branches, the ramus anterior and 
the ramus posterior. The ramus anterior divides into three branches— 
the ramulus ampulle anterioris, which extends to the anterior ampulla; 
“Contributions from the Zodlogical Laboratory of the Indiana University, No. 30. 
