EARTHWORM 65 



Make a diagram of a side view showing the location of the 

 reproductive organs found. Number segments. 



C. Reproduction in the Earthworm 



Because the earthworm has the reproductive organs of both 

 sexes functional in the same individual it is said to be hermaph- 

 roditic. During the breeding season earthworms come out of their 

 burrows at night for the purpose of copulation. Two individuals 

 come together with their heads pointing in opposite directions. 

 While in this position a mucus tube is secreted which holds the 

 two worms with their ventral surfaces together. This brings the 

 spermiducal pores of each in contact with the openings of the 

 spermathecae of the other. In this manner the spermathecae of 

 each worm become filled with sperm cells which have been pro- 

 duced by the other individual. This completes the act of copula- 

 tion and the two worms separate. 



Glands in the clitellum secrete a cocoon which is gradually 

 worked off toward the anterior end of the worm. As this cocoon 

 passes over segment XIV eggs are discharged into it. In the re- 

 gion of segments XI and X sperm cells are discharged into the 

 same cocoon and fertilize the eggs. These sperm cells are the 

 ones that were deposited in the spermatheca by an entirely dif- 

 frent individual during copulation. The cocoons are left in 

 moist places where the eggs undergo development, giving rise to 

 minute immature worms which break through the wall of the 

 cocoon. 



DIGESTIVE SYSTEM 



I. In all of this work remember that the septa may be 

 crowded either forward or backward by some of the organs. For 

 this reason it is necessary to observe in what cavities the organs 

 lie rather than observe the external body markings of segments in 

 the region occupied by the organs. If a structure occupies more 

 than one segment, the places where the septa crossed it are fairly 

 easily recognized. 



