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TEXTBOOK OF ZOOLOGY 



Reproductive Organs 



The earthworm is hermaphroditic, the organs of both sexes being 

 present in every animal. The seminal receptacles, oviducts, and 

 ovaries are female organs, and the testes and seminal vesicles are male 

 organs. The seminal vesicles are three pairs of light-colored bodies 

 located in segments IX, XI, and XII. In sexually mature individ- 

 uals they may extend back through the septae as far as the fifteenth 

 segment. If their contents are examined with a microscope, they 



Fig. 103. — Diagram showing reproductive system and nervous system in seg- 

 ments VIII to XV of an eartliworm. The seminal vesicles have been cut away in 

 somites X and XI to disclose the testes and sperm funnels, es, egg sac ; nc, nerve 

 cord ; ov, ovary ; sf, seminal funnel ; sm, septum between two somites ; sp, sperm 

 duct (vas deferens) opening in the fifteenth somite; sr, seminal receptacle; sv, 

 seminal vesicle; t, testis; vd, oviduct. (From White, General Biology, published 

 by The C. V. Mosby Company.) 



are seen to contain the various stages of developing spermatozoa 

 coming from the sperm mother cells. The testes are the two pairs 

 of very minute bodies projecting into the seminal vesicles in seg- 

 ments X and XI and cannot be seen without first removing the 

 dorsal part of the seminal vesicles. The union of the vasa effer- 



