RAMBLES ABOUT HOME. 



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 sun- 

 fish, of a fish that is strictly a diurnal species, of bright 

 coloration, and that passes through the various phases of 

 courtship and nidification without uttering a sound ; and 

 on the other hand, more or less in detail, referred to sev- 

 eral other fishes that are all of dull coloration, are noc- 

 turnal in their habits, and, whether voluntarily or not, 

 certainly at times do utter sounds. They can not be 

 considered as simply making such a noise as would 

 result from certain muscular movements. The action 

 that produces the sound, on the contrary, I have been 

 led to believe is intentionally performed in order that the 

 sound may result, and the fish intends it as a call, which 

 is responded to by those hearing it, and for whom it was 

 intended. 



When we carefully study the entire ichthyic fauna of 

 a given locality, say of a given stream, as I have done in 

 this case, there will undoubtedly be found some excep- 

 tions to this supposed rule of dissociation of coloration 

 and voice ; but these may be less in number than appear 

 to us, when we consider how many species are found in 

 every stream that are so diminutive that it can not be 

 determined to which class they really belong. Thus, 

 while many are dull-colored and doubtless possess voice, 

 it is too faint for us to hear ; but, from the fact that this 

 peculiarity can be determined in some of the larger spe- 

 cies, it is not improbable that in earlier geological eras 

 fishes generally were of somber tints, and possessed more 

 marked vocal powers than at present, and that, in the 

 subsequent differentiation of genera and species, color 

 was more and more evolved as a generic character, and 



