PUZZLES AND PARADOXES 267 



become separated from the brain, of which, as in all verte- 

 brates, it is an outgrowth : and further only one eye, in 

 the middle of the head, is present, recalling the third eye 

 in the middle of the head, of the ancient fish-lizards and 

 other reptiles. 



It is manifest, then, that the leathery, bag-like adults 

 are degenerate vertebrates ; kin to the fishes and the 

 frogs — nay, to man himself. How and why this change 

 has come about the wisest of us cannot tell, nor ever will. 

 The fact remains that for a day these youngsters endure : 

 then, as if cloyed with the sweets of liberty, or appalled 

 at the heritage that is theirs, they choose rather to vegetate 

 than to lead the Ufe of a healthy animal. The die once 

 cast, they settle down by the head to the nearest rock or 

 broad blade of fucus and speedily cast off all semblance 

 of their fleeting greatness. The tail, and rudiments of 

 the backbone are absorbed, the eye and brain vanish, 

 and they become leather bottles or mere shapeless masses, 

 glorified by a tincture of red, or blue, or black and white, 

 as the case may be. But for the evidence of these larvse 

 the most skilled anatomist would never have wrung this 

 extraordinary story from the adult : so that here again 

 we have convincing evidence of the importance of the 

 study of young animals. 



