1877.] Traces of a Voice in Fishes. 155 
utter a more distinctly musical sound than any other of those I 
have mentioned. It isa single note, frequently repeated, and has 
a slightly metallic resonance. I have heard this sound only at 
night, and never when the animal is taken from the water by 
day, as when captured by a hook, so that I presume it is not in- 
voluntary. When a large number of eels are congregated in a 
small space, as when feeding on some decayed animal, I have 
heard this note very frequently repeated, and from the volume 
of sound I judge that large eels utter only a note that is dis- 
tinctly audible. It is well known that this fish occasionally 
leaves the water voluntarily 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 suf- 
fer little inconvenience, as, snake-like, they crawl at night over a 
considerable stretch of land, guided by some undetermined in- 
stinct to the nearest water. At such a time the eel will occa- 
sionally utter this same clear note, especially if surprised. From 
what Ihave been able to determine concerning these overland 
journeys of the eel, they are undertaken only when the grass is 
well moistened with dew, and a surface of any extent devoid of 
thick vegetation is an effectual barrier to their progress. I 
would add, that I have noticed when *“ bobbing ” for eels, namely, 
catching them without injury to their mouths, that when squirm- 
ing about the bottom of the boat they not unfrequently utter this 
Same sound, not inaptly compared, perhaps, to the faint squeak 
of a mouse. 
I have given one instance, that of the common Pomotis, of 
a fish that is strictly a diurnal species, of bright coloration, and 
that passes through the various phases of courtship and nidi- 
fication without uttering a sound ; and on the other hand, more 
or less in detail, referred to several other fishes that are all of 
dull coloration, are nocturnal in their habits, and, whether volun- 
tarily or not, certainly at times do utter sounds. They cannot 
be considered as simply making a noise, this arising from the un- 
avoidable result of certain muscular movements. The action 
that produces the sound, on the contrary, I have been led to be- 
lieve is one intentionally performed that. the sound may result, 
and the fish has a distinct purpose in view in the latter, it being 
à call to others of its kind, which is responded to by the approach 
of those hearing it and for whom it was intended. | 
‘hen we carefully study the entire ichthyic fauna of a given 
locality, say of a single small stream, as I have done in this case, 
