542 C. M. Child. 



its anterior portion, was used by the right piece in movement, while 

 in the left no such use was observed. 



Forty-six Days after Section. (Figs. 59 and 60.) The two 

 pieces present the same differences in form and activity as before. 

 In the right piece (Fig. 59) the amount of new tissue is much 

 greater than before, especially anterior to the pharynx, and the 

 intestinal branches have grown well out into the new tissue in the 

 anterior region and to a less extent in the region posterior to the 

 pharynx. In the left piece, on the other hand, the changes are 

 only slight. The amount of new tissue is scarcely greater than 

 before, and the intestinal branches extend only a very short dis- 

 tance into the anterior region and are not visible elsewhere. 



One Hujidred and Six Days after Section. (Figs. 61 and 62.) In 

 the right piece (Fig. 61) the relative amount of new tissue has 

 continued to increase and regeneration of the left ganglion and 

 the left side of the pharynx is complete. The width of the new 

 tissue is greatest anterior to the pharynx undoubtedly in conse- 

 quence of the greater motor activity of this part and in this region 

 the intestinal branches extend out to the margin and at the anterior 

 end of the pharynx some branches extend posteriorly. Posterior 

 to the pharynx intestinal branches are also present though they 

 do not fill the new tissue so completely, and some of them extend 

 anteriorly at the posterior end of the pharynx. No intestinal 

 branches are present on the left side of the pharyngeal region 

 except those that extend into it from around the two ends. The 

 posterior end of this piece is now almost straight (compare Fig. 

 57); it has been subjected more frequently and in greater degree 

 than the other parts to longitudinal tension, since it is the chief 

 organ of attachment. 



The left piece, on the other hand, has not changed greatly. It 

 is possible that some degree of regeneration of the cephalic ganglia 

 has occurred, though new ganglia are not clearly visible; at any 

 rate more or less extension often occurs and results in bringing the 

 piece into the form shown in Fig. 62. The physical conditions of 

 the old tissues near the cut surface have gradually changed during 

 contraction and the new tissue, having arisen while the piece was 

 contracted, is capable of much less active extension than the old 



