TRACES OF VOICES IN FISHES. 443 



rily prisoners, even if direct water connection is broken.^ 

 In these ponds they grow to a large size and live to a 

 great age ; yet summer after summer passes without any 

 indication of their breeding. !No species of fresh- water 

 fish is more strictly nocturnal in its habits, and none are 

 so easily studied, inasmuch as at night they are not only 

 very active, but keep continually near the surface. In 

 the matter of voice, eels utter a more distinctly musical 

 sound than any other of the fish I have mentioned. It 

 is a single note, frequently repeated, and has a slight 

 metallic resonance. I have heard this sound only at 

 night, and never when they are taken from the water by 

 day, as when captured by a hook, so that I presume it is 

 not involuntary. "When a large number of eels are con- 

 gregated in a small space, as when feeding on some dead 

 animal, I have heard this note very frequently repeated, 

 and from the volume of sound I judge that large eels 

 only utter a note that is distinctly audible. It is well 

 known that this fish occasionally leaves the water volun- 

 tarily and wanders a considerable distance to other streams 

 or ponds ; and when through protracted droughts a pond 

 becomes quite dry, while other fishes perish, the eels 

 suffer little inconvenience, as, snake-like, they crawl at 

 night over a considerable stretch of land, guided by some 

 undetermined sense to the nearest water. At such times 

 the eel will occasionally utter this same clear note, espe- 

 cially if surprised. From what I have been able to de- 

 termine concerning these overland journeys, they are 

 undertaken only when the grass is well moistened with 

 dew, and a surface of any extent devoid of thick vege- 

 tation is an effectual barrier to their progress. I would 

 add that I have noticed, when "bobbing" for eels, or 

 catching them in a manner that inflicts no injury to their 

 mouths, that when squirming about the bottom of the 



