The Organs of Sense i 2 1 



b 



The lancelet shows no trace of an ear. In the cyclostomes, 

 hagfishes, and lampreys it forms a capsule of relatively simple 

 structure conspicuous in the prepared skeleton. 



The sense of hearing in fishes cannot be very acute, and is 

 at the most confined to the perception of disturbances in 

 the water. Most movements of the fish are governed by sight 

 rather than by sound. It is in fact extremely doubtful whether 

 fishes really hear at all, in a way comparable to the auditory 

 sense in higher vertebrates. Recent experiments of Professor 

 G. H. Parker on the kilHfish tend to show a moderate degree 

 of auditory sense which grades into the sense of touch, the tubes 

 of the lateral line assisting in both hearing and touch. While 

 the killifish responds to a bass-viol string, there may be some 

 fishes wholly deaf. 



Voices of Fishes. — Some fishes make distinct noises variously 

 described as quivering, grunting, grating, or singing. The name 

 grunt is applied to species of HcBmulon and related genera, and 

 fairly describes the soimd these fishes make. The Spanish name 

 ronco or roncador (grunter or snorer) is applied to several fishes, 

 both sci^noid and hsemuloid. The noise made by these fishes 

 may be produced by forcing air from part to part of the com- 

 plex air-bladder, or it may be due to grating one on another of 

 the large pharyngeals. The grating sounds arise, no doubt, 

 from the pharyngeals, while the quivering or singing sounds arise 

 in the air-bladder. The midshipman, Porichthys notatus, is often 

 called singing fish, from a peculiar sound it emits. These sounds 

 have not yet been carefully investigated. 



The Sense of Taste. — It is not certain that fishes possess a 

 sense of taste, and it is attributed to them only through their 

 homology with the higher animals. The tongue is without deli- 

 cate membranes or power of motion. In some fishes certain 

 parts of the palate or pharyngeal region are well supplied with 

 nerves, but no direct evidence exists that these have a function 

 of discrimination among foods. Fishes swaUow their food very 

 rapidly, often whole, and mastication, when it takes place, is a 

 crushing or cutting process, not one likely to be affected by the 

 taste of the food. 



The Sense of Touch. — The sense of touch is better developed 

 among fishes. Most of them flee from contact with actively 



