StnJirs oil Regulation 385 



Their accumulation in headless pieces must be due to the fact that 

 these pieces use the nutritive material less rapidly than those where 

 the head is present. This is to be expected from the differences 

 in activity between headless pieces and others. Moreover, it 

 will be shown in the following section that these products accumu- 

 late more rapidly and to a greater extent in the intestine as the 

 activity of the piece decreases. The absence of correlation 

 between intestinal degeneration and the accumulation of the prod- 

 ucts of degeneration within the intestine indicates very clearly 

 that the degeneration or persistence of the intestinal branches does 

 not depend primarily on nutritive conditions. If movements are 

 slight, intestinal degeneration may proceed more rapidly in pieces 

 where a considerable quantity of the detritus, which undoubtedly 

 possesses nutritive value, is present than in cases where the intes- 

 tine is almost empty. Thus, for example, in the case just dis- 

 cussed (Fig. 14) the intestinal branches in the prepharyngeal region 

 have undergone much more complete degeneration in 143 days 

 than in a normal animal (Fig. 2), although the products of degener- 

 ation have accumulated in the headless piece to a much greater 

 extent than in the other. 



In this case then, as in those discussed above, the visible regula- 

 tory changes in the intestine are very evidently primarily func- 

 tional regulations and are much more closely associated with the 

 mechanical than with the nutritive conditions, i.e., they are func- 

 tional regulations in response to mechanical stimuli. 



When a larger portion of the prepharyngeal region is removed, 

 the second pharynx appears nearer the old pharynx, until in cases 

 where the level of section is not far anterior to the old pharynx, 

 this may persist, or it may degenerate and a small pharynx appear 

 in approximately the same position (Child '05c). These cases 

 present no new features of special importance as regards intestinal 

 regulation. In some pieces the occlusion of the intestine by the 

 pharynx or pharynges appears to be less complete than in others, 

 and in such cases the peculiar conditions shown in Fig. 14 are less 

 marked. 



When the level of section lies immediately posterior to the old 

 pharynx, a new pharynx is often formed at the anterior end of the 



