310 FISHES 



is not stated that the male salmon is smaller than the female, 

 the sex of large specimens not being usually given in the re- 

 cords. It is certain that the male of the dragonet (see Plate 

 XXV.)> which is remarkable for its activity in courtship and 

 rivalry with other males, though it can scarcely be said to fight, 

 is considerably larger than the female. The same is the case 

 with Coris julis, a species of wrasse occurring in the Mediter- 

 ranean, in which secondary sexual characters are well marked 

 though its sexual habits have not been described ; the male at- 

 tains a length of sixteen centimetres or six inches while the 

 female does not exceed five inches. In the Scald-fish, Arno- 

 glossus latema, also, the males are distinguished by pronounced 

 secondary characters and attain to a larger size than the females. 

 Thus in fishes as in mammals, birds, and other animals, greater 

 size seems to be constantly associated with greater activity on 

 the part of the males in connection with reproduction, whether 

 the activity is shown in actual fighting with rivals or in other 

 results of sexual excitement. 



The changes which take place in the males of the species of 

 Onchorkynckus, the salmon of the Pacific, at the spawning- 

 season are as follow : both jaws become greatly prolonged and 

 hooked, so that either they close by the side of each other like 

 shears, or cannot be closed at all, the front teeth grow to a 

 great length, as much as half an inch, the body grows more 

 compressed and deeper at the shoulders so that a distinct hump 

 is formed, the scales become covered by spongy skin, the colour 

 changes to various shades of black and red according to the 

 species. In the dragonet, Callionymus lyra, (Plate XXV.) the 

 male is much larger and the anterior rays of his first dorsal fin 

 are greatly elongated, as well as the second dorsal and the ventral 

 to a less degree ; the sides of the body and head and the surface 

 of the vertical fins are ornamented with alternate bands of bright 

 blue and yellow, while the female is a dull mottled brown. The 

 actions of the male correspond to these peculiarities ; he can 

 scarcely be said to fight, but he rushes about in a state of great 

 excitement, trying to frighten other males, and erecting all his 

 fins and showing off his colours before the females. These 

 antics lead up to an actual pairing, for although in this species 

 fertilisation is external and the eggs are buoyant and free, the 

 male lifts the female by placing his pelvic fin under hers and 



