Chap. XII. FISHES. 23 



mental characters, the males originally varied, with their 

 variations transmitted to the same sex, and accumulated 

 throuo^h sexual selection bv attractins: or excitino: the 



O t/ ~ CD 



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 purpose. 



The last point which need be noticed is that in many 

 parts of the world fishes are known to make peculiar 

 noises, which are described in some cases as being 

 musical. Very little has been ascertained with respect 

 to the means by which such sounds are produced, and 

 even less about their purpose. The drumming of the 

 Umbrinas in the European seas is said to be audible 

 from a depth of twenty fathoms. The fishermen of 

 Eochelle 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." ^"^ If this 

 statement is trustworthy, we have an instance in this, 

 the lowest class of the Vertebrata, of Avhat we shall 

 find prevailing throughout the other vertebrate classes, 

 and which prevails, as we have already seen, with 

 insects and spiders ; namely, that vocal and instru- 

 mental sounds so commonly serve as a love-call or as 

 a love-charm, that the power of producing them was 

 probably first developed in connection with the propa- 

 gation of the species. 



3'" The Kev. C. Kingsley, in ^Nature,' May, 1870, p. 40. 



