Stiulit's on Reguiaiioji 383 



features of reduction. Ihe condition ot the intestine and the 

 visible movements of the intestinal contents in these and similar 

 pieces in the later stages indicates that in the course of reduction 

 in size the intestine sooner or later becomes occluded in the region 

 of the pharynx or pharynges. During reduction in size the old 

 pharynx is not reduced proportionally and in pieces w^hich have 

 been without food for several months it is often so large in propor- 

 tion to other parts as to cause a bulging of the body-wall dorsally 

 and ventrally in its region. It is probable that in such cases the 

 pressure upon the intestine in the pharyngeal region is sufficient 

 to prevent to a large extent the passage of intestinal contents 

 through it. Similarly the development of a new pharynx, posterior 

 to the old, as in Fig. 14, may likewise sooner or later occlude the 

 slender axial intestine in this region. This being the case, the 

 intestinal contents in the prepharyngeal and postpharyngeal 

 regions do not enter the "interpharyngeal" region to any great 

 extent, if at all. Consequently the course of intestinal regulation 

 in this region is largely independent of that in other parts of the 

 body. In the case shown in Fig. 14 this region contains but 

 little fluid and both axial intestine and branches are slender, but 

 since removal of the anterior end does not modify the muscular 

 activities in this region except quantitatively to some extent, the 

 branches have not entirely disappeared. 



In the prepharyngeal region (Fig. 14), on the other hand, con- 

 ditions are widely different. Here the axial intestine is greatly 

 distended with a large amount of the dark substance. If Fig. 14 

 be compared with that portion of Fig. i posterior to the level c, 

 which represents approximately the proportions of the piece at 

 the time of section, it will be observed that the prepharyngeal 

 region of the piece has decreased in size much more than the post- 

 pharyngeal region, doubtless, as was suggested in an earlier paper 

 (Child '05c), because the energy of functional conditions in this 

 region underwent a greater decrease with the loss of the head than 

 in the postpharyngeal region, and so the former region has served 

 in part as nutritive material for the latter. But the effect of this 

 reduction in size on the intestine has been to hasten degeneration 

 of the lateral branches in this region, since the movements of intes- 



