Studies oil Regulation 



365 



remain in the terminal regions ot the body. 

 With approach toward the middle the length ot 

 the branches increases until in the pharyngeal 

 region they still retain their full length, though 

 they are less distended than originally. At the 

 beginning of the experiment the intestine of the 

 specimen figured presented the condition indi- 

 cated in Fig. 2. 



Undoubtedly intestinal reduction could be car- 

 ried further in normal animals, but departure 

 from Naples made it impossible to keep the speci- 

 mens under observation longer. 



Intestinal reduction in this species consists in 

 an atrophy and disintegration of the more distal 

 portions of the intestine, not merely in a reduc- 

 tion in size or contraction. Various stages can 

 be more or less clearly distinguished, in most 

 cases, though of course each gradually passes mto 

 the following. 



Starting with the normal well-filled intestine as 

 in Fig. 2, or Fig. i, the first changes consist in de- 

 creasing distension, so that the individual branches 

 become more clearly distinguishable. . Somewhat 

 later the distal portions of these branches disinte- 

 grate and form a longitudinal band of dark granu- 

 lar substance, which appears somewhat like a longi- 

 tudinal canal on each side connecting with the 

 lateral intestinal branches (Fig. 3, also the pharyn- 

 geal region in Fig. 6). Under high magnification, 

 however, these longitudmal bands are clearly seen 

 to be the debris of the disintegrated terminal 

 regions of the branches. The lateral bands make 

 their appearance first in the more terminal regions 

 of the body and progress toward the middle 

 regions as the ends of the branches undergo 

 degeneration. 



But a part of the products of degeneration 



d 



h 



m 



Fig. 



