NUCLEATED CELLS. 39 



the most important of those metamorphoses, which 

 its alleged successive progenitors in the course of 

 innumerable generations slowly underwent by evolu- 

 tion, towards the form of its more immediate ancestors. 

 Thus in the course of the development of a human 

 being in utero> the embryo, at a certain stage some- 

 what resembles a fish, by and by a frog-like creature, 

 and next a mammal the mammalian form, be it 

 observed, appearing first like that of the Monotremata 

 or ornithorhyncus tribe the lowest of the class ; then 

 like that of the Marsupialia or kangaroo tribe 

 afterwards like that of quadrupeds and apes, until, 

 at last, the perfect human form is attained. 



But before even the embryo appears, the ovum 

 itself, in the various preliminary metamorphoses it 

 undergoes in consequence of fecundation, presents 

 to the eyes of Evolutionists recapitulations of the 

 primaeval and very simple forms which constituted, 

 they allege, the beginnings of the phylum or line of 

 man. 



The facts and arguments adduced by Haeckel 

 in support of these evolutionary views I proceed to 

 examine. 



What is called a nucleated cell is a microscopical 

 corpuscle of albuminous nature in respect to substance ; 

 and in respect to structure comprising two essentially 

 distinct parts, viz. protoplasm and nucleus. These 

 two parts may be enclosed within a membraneous 

 vesicle a third element of structure, but this cell- 



