126 evolution: the ages and tomorrow 



several ganglia along the forepart of the nerve trunk, and 

 found that the earthworm could still learn to master the T 

 maze as long as some large proportion of the segmental 

 ganglia were left. 



Like many other organisms, some of the annelids have an 

 incredible genius for the astronomical timing of events of 

 the cosmos. The palolo, a womi of the tropical seas near the 

 island of Samoa, is almost as rehable as the calendar. These 

 anneUds live on the sea floor in crannies among the rocks 

 and coral growths. They breed in October and November 

 and every year, faithful to the day, they appear in huge 

 swarms at the surface of the sea for the wedding dance. 

 With the palolo, spawning is at dawn for two days in Octo- 

 ber and two in November. They begin to appear at the sur- 

 face the day before the first quarter of the moon and within 

 24 hours are present in such enormous numbers that they 

 color the sea a brownish indio^o. The mature sexual worms 

 with special swimming modifications are several inches long, 

 the males being brown and the females indigo and green. 

 The males are terrifically agitated and pass on the excite- 

 ment to the females in a wild, wriggling dance. Eggs in 

 endless multiples of astronomical numbers are spawned and 

 fertilized in the two days of breeding. Through the years the 

 human natives of the islands have been affected by the sexual 

 cycle of these worms, and at the October and November 

 dates there is feasting and festival. Would anyone seriously 

 contend that all this chemistry of excitement, this high 

 physiological activity, and sexual stimulus of the nervous 

 system of the palolo at the time of breeding, are not accom- 

 panied by any degree of consciousness? 



The basic nervous system of the molluscs (snail, clam, 

 octopus, etc.) is similar to that found in the segmented 

 womis. There is a ring-like ganglion around the gullet 

 which heads the rest of the nervous system. There are two 

 nerve trunks, one going to subsidiary ganglia in the peculiar 

 moUuscan foot, the other going to ganglia that control the 



