54 DE GENERA TION. 



the reader who has so far followed me in these pages. 

 Suppose, as might well have happened, that the 

 Barnacles, one and all, instead of recapitulating in 

 their early life, were to develop directly fivvi the egg to 

 tJie adult form, as so many animals do ; should w^e 

 have ever made out that they were degenerate Crus- 

 taceans ? Possibly we should : their adult structure 

 still bears Important marks of affinities with crabs and 

 shrimps ; but as a matter of fact before their recapitu- 

 lative development had been discovered they were 

 classed by the great Cuvier and other naturalists with 

 the Molluscs, the mussels and snails. 



Suppose again that all the existing Ascidians, 

 as many of them actually have, had long ago lost 

 their recapitulative history in growth from the ^g^ : 

 suppose that no such a thing as an Ascidian tadpole 

 existed, but that the Ascidian's ^<g^ grew as directly 

 as possible into an Ascidian, in every living species 

 of the group. This might easily be the case. Then 

 most assuredly we should not have the least notion 

 that the Ascidians were degenerate Vertebrates. We 

 should still class them where they used to be classed 

 before the Russian naturalist Kow^alewsky discovered 

 the true history and structure of the Ascidian tadpole. 



