THE TUBE-WITHIN-A-TUBE BODY PLAN 



189 



and live in the open ocean catching their 

 prey in flight, whereas others such as the 

 sea mouse (Fig. 10-12) crawl over the 

 ocean floor. Many construct burrows out of 

 mucus, such as Chaetopterus (Fig. 10-13); 

 others bore into rocks to provide a home for 

 themselves. Some are highly colored, such 

 as the peacock worm (Fig. 10-14) which 

 could easily be mistaken for a flower. 



Many of these worms have spectacular 

 breeding habits. One, the palolo worm 

 (Eunice viridis) of Samoa and Fiji, spawns 

 in a most remarkably regular and peculiar 

 manner. On the first day of the last quarter 

 of the October-November moon, the pos- 

 terior portion of the worm, heavily laden 

 with eggs or sperms, breaks off from the 



Fig. 10-T2. Aphrodite {AphrodHa hastata), the sea 

 mouse, from ventral view which definitely establishes 

 it as an annelid. From the dorsal side it resembles a 

 furry animal, hence its name. It is about 12 cm. long. 



Fig. 10-13. This annelid (C/iaefopferus) lives in a tube 

 secreted by its own body. The appendages are used 

 as paddles to keep the water circulating through its 

 tube, thus bringing in oxygen and small animals 

 upon which it feeds. It Is luminescent, which seems 

 strange since there is no opportunity for any other 

 animal to appreciate its beauty. This female speci- 

 men, which is removed from its burrow, is about 15 

 cm. long. 



parent worm and swims to the surface 

 where the gonadal products are discharged. 

 The surface of the sea is milky white with 

 the great numbers of these cells. Natives, 

 who are familiar with the exact time of 

 spawning, collect these worms when they 

 are about to spawn and feast on them. 



The earthworm 



No discussion of the phylum Annelida is 

 complete without a study of the lowly 

 earthworm, spurned by the squeamish and 

 cherished by the fisherman and robin. It 

 seems striking; that this creature, which is 

 so helpless when removed from its burrow, 

 has been able to spread its kind over nearly 



