NUCLEATED CELLS. 39 



III 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 



1 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, 



I 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 ; 

 i 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- 



