178 THE COURTSHIP OF ANIMALS 



nature of the secondary sexual characters which they 

 exhibit, and more definite information can be obtained 

 from such species as can be kept in aquariums. From 

 these two sources enough has been gleaned to show that 

 these cold-blooded creatures, in many cases, exhibit the 

 same emotions and the same means for their fulfilment 

 as the higher vertebrates. And it is significant that 

 wherever anything approaching what may be called 

 ** Courtship " obtains, the males commonly exhibit 

 secondary sexual characters, whether in the form of 

 ornament or of armature ; while among species which 

 consort in shoals during the breeding season no such dis- 

 tinctions are present. The ova and milt are shed and 

 fertilization takes place as they escape. 



Comment is frequently made in works on Natural 

 History on the fact that among fishes the males are 

 commonly smaller, often conspicuously so, than the 

 females. Among mammals the males are the larger ; 

 but among birds this is by no means always the case. It 

 is somewhat surprising to find this discrepancy among 

 the birds of prey, where, as in the case of the Sparrow- 

 hawk, the male is little more than half the size of his 

 mate ; commonly, however, there is little or no difference. 

 Among the fishes the differences are often much more 

 marked, as for example in the Conger-eel, wherein the 

 male never exceeds a length of two feet six inches or a 

 weight of one pound ; females, on the other hand, may 

 exceed eight feet in length and attain a weight of one 

 hundred and twenty-eight pounds, though such giantesses 

 are rare, but specimens of fifty pounds and upwards 

 are frequently met with. The explanation of this may lie 

 in the fact that among fishes it is no uncommon thing to 

 and males becoming sexually mature long before they 



