60 



ZOOLOGY. 



The common earth-worm (Fig. 66) is cylindrical and 

 many-jointed. The small mouth opens on the under side 

 of the first segment. The earth-worm is able to climb per- 

 pendicularly up boards or the sides of buildings by minute, 



Fig. 65.— Large leech, natural size, a, a tooth; c, head enlarged ■with the eyes; 

 t, triradiate teeth; V ', view of the three teeth, enlarged. Gissler, del. 



short, curved bristles, which are deeply inserted in the mus- 

 cular walls of the body, and arranged in two double rows 

 along each side of the body (Fig. 49*). In burrowing it 

 thrusts the pharynx into the end of the head, causing it to 





