Chap. XII. Fishes. 347 



accordance with the usual rule throughout the animal kingdom^ 

 the more attractive males. 



On the whole we may conclude, that with most fishes, in 

 which the sexes differ in colour or in other ornamental charac- 

 ters, the males originally varied, with their variations trans- 

 mitted to the same sex, and accumulated through sexual 

 selection by attracting or exciting the females. In many cases, 

 however, such characters have been transferred, either partially 

 or completely, to the females. In other cases, again, both sexes 

 have been coloured alike for the sake of protection; but in 

 no instance does it appear that the female alone has had her 

 colours or other characters specially modified for this latter 

 purpose. 



The last point which need be noticed is that fishes are known 

 to make various noises, some of which are described as being 

 musical. Dr. Dnfosse, who has especially attended to this 

 subject, says that the sounds are voluntarily produced in several 

 ways by different fishes : by the friction of the pharyngeal bones 

 — by the vibration of certain muscles attached to the swim- 

 bladder, which serves as a resounding board — and by the vibra- 

 tion of the intrinsic muscles of the swim-bladder. By this lattei 

 means the Trigla produces pure and long-drawn sounds which 

 range over nearly an octave. But the most interesting case for 

 us is that of two species of Ophidium, in which the males alone 

 are provided with a sound-producing apparatus, consisting of 

 small movable bones, with proper muscles, in connection with 

 the swim-bladder. 41 The drumming of the Umbrinas in the 

 European seas is said to be audible from a depth of twenty 

 fathoms ; and the fishermen of Bochelle assert " that the males 

 " alone make the noise during the spawning-time ; and that it 

 " is possible by imitating it, to take them without bait." 42 From 

 this statement, and more especially from the case of Ophidium, 

 it is almost certain that in this, the lowest class of the Verte- 

 brata, as with so many insects and spiders, sound-producing 

 instruments have, at least in some cases, been developed through 

 sexual selection, as a meaus for bringing the sexes together. 



41 ' Comptes Rendus.' Tom. xlvi. the Dutch translation of this work 



1858, p. 353. Tom. xlvii. 1858, p. (vol. ii., p. 36), gives some further 



916. Tom. liv. 1862, p. 393. The particulars on the sounds made by 



noise made bv the Umbrinas (Scunia iishes. 



aiuila), is said by some authors to 42 The Rev. C. Kingslcy, ic 



»e more like that of a rlute or organ, ' Nature,' May 1870, p. 40. 

 lhau drumming: Dr. Zuuteveen, in 



