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THE AMEBIC AN NATURALIST [Vol. XLIII 



edge of parasitic worms, has attributed a glandular func- 

 tion to these cells, but, as we have seen, has interpreted 

 them in quite a different way. 



Summary 



1. The cuticula of trematodes and cestodes is not 

 homologous to that of other worms and of arthropods. 



2. The cuticula of trematodes and cestodes is the per- 

 ipheral portion of the parenchyma, being composed 

 mainly of secretions of it. 



::. 'I'hc subcuticula is not an epithelium or a hypo- 

 dermis, hut belongs genetically to the parenchyma. 



4. The subcuticular cells are not present in the mono- 

 genetie trematodes, in most of the Aspidobothridae and in 

 many digenetie trematodes, or in any trematodes or ces- 

 todes during the earliest larval stages when the cuticula 

 first forms. 



5. The function of these cells is not known, and although 

 most authors have ascribed a glandular or secretory func- 

 tion to them it seems likely that they form an indifferent, 

 embryonic tissue which develops into specialized tissues 

 as the worm increases in size. 



LITERATURE 



