in] OTHER DEFINITIONS 73 



That is its structure when young : at the close of 



,e 



Fig. 5. Diagram of a Pilidiuin with }~oung Nemertine enclosed. 

 b, band of special long cilia ; e, envelope enclosing the worm ; 

 w, mouth ; ?i, the young worm ; g, stomach. (Magnified.) 



its life, however, it is seen to contain a darker some- 

 thing within itself, and this something on closer 



