ANATOMY OF THE EARTHWORM. 151 



cular, white sacs, situated just outside the testcs, between 

 the ninth and tenth and the tenth and eleventh segments 

 (Fig. 85, e). 



(i.) Remove one of them, and examine its contents 

 with the microscope. It will be found to be filled with a 

 compact mass of fully-developed spermatic filaments. 



g. The detection of the ovaries and oviducts is a matter 

 of some difficulty. In a large specimen, which has been 

 pinned out under alcohol, on the ventral surface of the 

 thirteenth segment, close to the nerve cord, are a pair of 

 small, white, pear-shaped organs, about one-sixteenth of 

 an inch long, the ovaries (Fig. 85, ?). 



They are attached by their stalks to the ventral body 

 wall, and a microscopic examination shows that they are 

 membraneous sacs, without ducts, and filled with ova, in 

 all stages of development. The ripe ova escape, by the 

 rupture of the walls, into the body cavity, and are then 

 taken up by the mouths of the oviducts. 



h. The oviducts are a pair of small, trumpet-shaped, 

 ciliated tubes, which open externally by their small ends, 

 near the inner setae of the fourteenth segment (Fig. 85, m). 

 The inner, enlarged end of each oviduct bends forward, 

 passes through the partition between the thirteenth and 

 fourteenth segments, and opens in the cavity of the thir- 

 teenth segment by a large, funnel-shaped, ciliated mouth, 

 which is close to the ovary of the same side. 



10. The integument. After the viscera have been re- 

 moved, the longitudinal muscles of the body wall may be 

 examined. 



They consist of 



a. A large ventral band. 



b. Two lateral bands. 



c. A dorsal band. 



