20 GENERAL BIOLOGY. 



each side, which runs back and opens 

 to the outside in the 15th somite. 



(d) The testes : four small, opaque white 



bodies with, finger-like lobes, attached 

 one on each side of the median line to 

 the posterior side of the dissepiments 

 9-10 and 10-11. In the mature speci- 

 men they are enclosed by the median 

 seminal vesicles. 



(e) The seminal receptacles : two pairs of white, 



rounded sacs in the 9th and 10th 

 somites. Their short ducts open to 

 the outside in the constrictions be- 

 tween the 9th and 10th and the 10th 

 and 11 th somites, respectively. 



(/*) The ovaries: two pear-shaped bodies at- 

 tached to the anterior wall of the 13th 

 somite, one on each side of the median 

 line. 



(g) The oviducts: two short, funnel-shaped 

 tubes passing through the dissepiment 

 between the 13th and 14th somites, one 

 on each side of the median line. They 

 appear often as thickenings of the dis- 

 sepiment. 

 Make an enlarged diagram of the reproductive 



organs. 

 7. The nervous system. 



Central nervous system. Observe: 



