302 POLYGORDIUS 



The rest of the development of Polygordius may be 

 summarized very briefly. The trunk grows so much faster 

 than the head (pro- plus peri-stomium) that the latter under- 

 goes a relative diminution in size, finally becoming of equal 

 diameter with the trunk as in the adult. The ciliated rings 

 are lost, the tentacles grow to their full size, the eye-spots 

 atrophy, and thus the adult form is assumed. 



