9 6 



C. M. CHILD. 



November i . Eight days after 'section. On the oral end 

 of the piece the oesophagus and body-wall have united about 

 the whole circumference of the body, the usual result in such 

 cases ; the free surfaces of the body-wall formed by the trans- 

 verse cut have not united with each other, but each has united 

 with the corresponding cut cesophageal surface. Fig. 2, 1 a dia- 

 grammatic longitudinal section of the body at this stage, shows 

 what has occurred more clearly than is possible by description. 

 It is evident that that part of the body directly over (i. e., oral to) 

 the lateral cut has closed in such a manner that its enteric cavity 



FIG. i. 



FIG. 3. 



is not in communication with that of other parts of the body nor 

 with the exterior. Orally and aborally it is closed by the union 

 of oesophagus and body-wall ; each intermesenterial chamber is 

 separated from adjoining chambers by the intervening mesentery. 

 Thus, as regards this region, conditions are similar to those ex- 



1 The different regions are distinguished in these figures in a somewhat conven- 

 tional manner. The old body-wall is represented by two heavy lines (ectoderm and 

 entoderm ) with fine longitudinal lines indicating the longitudinal muscles between 

 them. The cesophageal region is represented by a very heavy single line and regen- 

 erated regions by a much lighter single line. In Figs. 7 and 8 portions of old disc 

 and tentacles are represented by a double line and regenerated disc and tentacles by 

 a single line. 



