I lO 



C. M. Child. 



The cut surface in this piece was a short distance posterior to thc^ 

 cephalic ganglia. Figure 2 represents the piece five days after 

 section, Figure 3 ten days after section, and Figure 4 twenty-seven 

 days after section. The new tissue is bilaterally symmetrical at 

 all times and growth appears to occur most rapidly along the me- 

 dian plane. The gradual decrease in size of the whole is due of 

 course to the absence of food. The course of posterior regenera- 

 tion in Planaria, as described by Morgan and others, is similar, 



Fig-. 2. 



Fig. 3. 



Fig-. 4. 





F^g. 5. Fig. 6. .Fig. /, 



though the amount of new tissue formed is relatively less than in 

 Leptoplana; similar results have also been obtained by others 

 with various forms. 



If the cut surface from which regeneration occurs be oblique 

 instead of transverse the course of regeneration differs in some 

 respects from that just described. Figures 5-7 illustrate the his- 

 tory of such a piece, begun on the same day as the pre- 



