ALTERNATE GENERATION. 



43 



afflicted with tape-worm, issue so-called somites or seg- 

 ments of the tape-worm. These somites are usually 

 filled with such an extraordinary number of ova that 

 they seem like mere packets of eggs. It appears, how- 



FIG. 3. 



ever, from the evolutionary history of the tape-worm, 

 and its relations with other annulosa, namely with 

 leeches and Turbellaria, that notwithstanding their in- 

 completeness and deficiency of organs, these somites are 

 equivalent to sexually mature individuals ; or, according 

 to Haeckel's definition, are endowed with personality. 

 If the tape-worm now comported itself like most other 

 animals, somites would be directly developed from its 

 eggs. But to this there is a very circuitous proceeding. 



