224 THE INFANCY OF ANIMALS 



been given. As regards the latter surely the most remark- 

 able of all is that furnished by the young of the Horse- 

 mackerel (Caranax trachurus). These, as if by some 

 mysterious process of divination, seek shelter from pre- 

 datory foes beneath the umbrella of jelly-fish, where 

 they are effectually shielded from attack by the powerful 

 batteries of stinging cells with which the pendant tentacles 

 of jelly-fish are armed. How do they know, these tiny 

 atoms, that under such guardianship they are secure f 

 We cannot suppose that they do know. But this makes 

 the association the more mysterious. We meet with one 

 other similar case in the " Man-of-war fishes " {Nomeus 

 gronovii), which shelter in like manner among the tentacles 

 of the Portuguese Man-of-war (Physalia). But these are 

 adult, not larval fishes ; and their guardian seems to 

 levy toll on their ranks, at least occasionally, by eating 

 one or more of those who have sought sanctuary. At any 

 rate dead Man-of-war fishes have been found within the 

 stomachs of the jelly-fishes. 



Notwithstanding the numerous and varied instances of 

 parental care among fishes, the majority of species, as we 

 have already remarked, make no provision for their young, 

 but lay an enormous number of eggs. These, of necessity, 

 contain little or no food-yolk ; and in consequence the 

 young fish hatches long before it has acquired its adult 

 shape, or rather the form of its parents. They enter 

 the World, in other words, as larvae. In many cases these 

 larvae present quite extraordinary forms, displaying 

 structural peculiarities the meaning of which we can 

 only guess at, and often we cannot do even this. 



The young of the Ribbon fish afford an illustration of 

 one of these enigmas. In the form of the body it is 

 totally unlike the adult, for in the first place it is very 



