234 METAMOEPHOSES OF MAN 



Scyphistoma, as tlie Ephyra is the larva of the 

 Aurelia. 



Among the Distomidse the phenomena are still 

 more complicated, for we find at the same time three 

 modes of development, and three processes of meta- 

 morphosis properly so called. The ovum gives rise, 

 by transformation y to a ciliated larva, which, by 

 geneagenesis, produces a Sporocyst, that in its turn 

 attains its final form by metamorphosis. The multi- 

 plication by buds, of the Sporocysts themselves, and 

 of the Cercariae, must be referred to geneagenesis. The 

 Cercariaa are the true larvae of the future Distomae ; and 

 when they lose their tails and become encysted and 

 motionless, is it not in order to pass into the nymph 

 condition, after the fashion of the Stratiomys ? And 

 when, finally, they rise from this torpid state, under 

 the form of Distomee, is it not by a true metamorphosis 

 comparable in every respect with that from which the 

 perfect insect results ? 



So far from geneagenesis being a modification of 

 metamorphosis, the facts established by the first 

 tend rather to modify the most generally accepted 

 ideas which have been confirmed by the second. 



Assuredly, if up to the present, there is any ad- 

 mission to be made, it is that the offspring is the 

 direct product of the parent; that the individuality 

 of the germ is maintained from its birth* till its death. 

 So far as reproduction by buds has been considered 

 as fundamental a process as reproduction by ova, 

 these views apply equally to both. Metamorphosis 

 does not affect them in this particular. No matter 

 how numerous and complete the changes are which 

 a butterfly undergoes, the animal is still one being \ 



