124 



P. B. SIVICKIS. 



posterior to the genital pore, the last region to disintegrate being 

 that between the mouth and the genital pore. Commonly the lat- 

 eral margins of the body disintegrate somewhat earlier than median 

 regions at the same level, but in some individuals these transverse 

 differences do not appear, and in some the median region appar- 

 ently disintegrates earlier than the margins. There is not much 

 difference between dorsal and ventral, but ventral regions usually 

 disintegrate slightly in advance of dorsal (Fig. n). 



0$®$k. ,4^S§Sv.; '■$$&!• 



Alj 



J, 



III 



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8 



10 



II 



Figs. 7— 11. Susceptibility gradients in P. lata, as shown by KNC m/1000: 

 Figs. 7—10, stages in progress of disintegration in dorsal view; Fig. 11, a 

 stage of disintegration in lateral view to show difference between dorsal and 

 ventral. 



It should be noted that these statements concern primarily the 

 body wall, but they appear to hold good for the parenchyma also. 

 In well-fed animals the digestive tract is highly susceptible and, 

 even though the cyanide must pass through the body wall to reach 

 it, the digestive tract usually swells and disintegrates earlier than 

 the body wall and often bursts through the latter at various points. 

 In starved animals the digestive tract is much less susceptible and 



