ANNELIDS IN GENERAL 



249 



leech, however, has in the past been of service to physicians and played 

 such a part in medicine in the sixteenth century as to earn for the phy- 

 sician himself the appellation of leech. Most other annelids are of little 



A sex u a/ 

 zooiof 



Sexual 

 zoo id 



yy- 



Fig. 150. — A palolo worm, Eunice viridis (Gray), showing asexual and sexual zooids. 

 {From VanCleave, "Invertebrate Zoology," after Woodworth, by the courtesy of McGraw-Hill 

 Book Company, Inc.) 



importance, though some are used as fish bait. In the South Seas a 

 worm known as the palolo (Fig. 150) is gathered by the natives when it 

 swarms in the breeding season in October and November and is used as 

 food, being considered a great delicacy. 



