190 



THE GENESTS OF SPECIES. 



[Chap. 



Secondly, as regards the last-mentioned author's expla- 

 nation of such serial homology as exists in the centipede 

 and its allies, the very groundwork is open to objection. 

 ^Fultiplication l)y s})ontaneous fission seems from some 

 recent researches to be much less frequent than has been 



AN ANNELID DIVIDING SPONTANEOfSI.Y. 



(A new head having been formed towards tlie hinder end of the body of the parent.) 



supposed, and more evidence is required as to the fact of 

 the habitual propagation of amj planaria?. in such fashion.^ 



1 Dr. C()l)l>ul(l has inlurnictl tli*' autlior that he has lu'vcr observed a 

 jtlnnarin (li\'i(le spontaneously, and lie is see]itieal as to that }»rocess taking 

 place at all. Dr. H. Charlton Bastian has also stated that, in spite of 

 much observation, he has never seen the process in vorticclla. 



