Annulata. 



9 1 



travel with the pos- 

 terior end fore- 

 most, as it does 

 occasionally, it has 

 but to point the 

 spines forward, 

 and the same action 

 of the muscles will | 

 propel it posterior 

 end foremost. If * 



w 



the worm were jf 



lying on a perfectly | 3 



smooth surface, on ^ 



which there was 1" 



C C/2 



no friction what- * 

 ever, the shorten- | " 



O ^ 



ing and lengthen- jg 

 ing of the body | 

 would avail noth- <r ^ 



n 90 



ing in the way 5- g 

 of locomotion; it ' | 

 would be simply S. s 

 motion. The loco- 

 motion of the earth- "|. 

 worm, however, is | 

 not essentially | 

 different from that 

 of other animals, 

 they must all 

 have some point of 

 support or resist- 

 ance by means of 

 which they pro- 



