188 



E. H. HARPER. 



13 



I 3 /,. 



16. 



DESCRIPTION OF FIGURES. 



FlG. II. Regeneration of a sexual individual after removal of first three segments. 

 The clitellum is indicated by the widening of the body. It takes in the fifth seg- 

 ment, which is a part of the pharyngeal region. The setse are absent from the clitel- 

 lum. One pair of ventral bundles were left in front of the clitellum. In stage (e) 

 the head segment is regenerated. As no more pairs of setse bundles were produced, 

 the regenerated part is regarded as the equivalent of the head segment alone. The 

 stages (b-e) followed 3, 8, 12 and 19 days after the operation, respectively. 



FIG. 12. Failure of regeneration after severing part of first segment in a sexual 

 individual. In (l>) a side view is given. The condition shown in (l>) and (f) 

 followed seventeen days after the cut. 



