THE RINGED WORMS OR ANNELIDS 



.f 



ened, forming the clitellum, which has an important func- 

 tion in relation to reproduction. Nearly 

 all the segments are furnished with minute 

 bristles, or setae, which are arranged in 

 four double rows. These may be seen 

 with a hand lens, or felt with the finger, 

 especially when it is rubbed from behind 

 forward over the ventral surface. These 

 setae can be protruded or withdrawn into 



V 



FIG. 97. FIG. 98. 



FIG. 97. Earthworm from dorsal side, cl, clitellum; p, prostomium. 

 (After Hatschek and Cori.) 



FIG. 98. V, ventral; L, lateral view of earthworm, cl, clitellum; o, 

 opening of oviduct; sp, opening of sperm duct; m, mouth; p, prostromium. 

 (After Hatschek and Cori.) 



special sacs, and they materially assist the worm in 

 locomotion. 



