232 S. SAGUCHI 



His figure 5 to 7 and 8, rather, appear to me evidently to show 

 an alveolar structure of the cuticular border. 



3) The intestines of Helix, Anodonta, Lumbricus and Limax, and 

 the hepatic duct of Helix belong to this group. Before proceeding 

 to describe the ciliated cells it will be necessary to say a few 

 words with regard to the structure of the cuticle of non-ciliated 

 intestinal cells. There are three opinions with regard to this 

 question: (1) the cuticle is perforated by small vertical canals 

 (Kolliker, Funke) ; (2) it is provided with rods (R. Heidenhain) ; 

 (3) it is composed either of coarser or of slender, finger-shaped 

 rods (Studnicka). In intestinal cells of the invertebrates studied, 

 I have found that the cuticle has, viewed 'in profile, an appear- 

 ance of longitudinal striation, seemingly caused by a parallel 

 arrangement of rods; the clear vertical narrow lines correspond 

 to the spaces between them. In surface view, minute, round, 

 clear pores appear scattered over the cuticle. These facts point 

 to the canalization of the latter, as KoUiker and Funke maintain. 



The structure of the cuticle of cihated cells is the same as that 

 of the non-ciliated and can readily be observed in the functional 

 change of the former, that is to say, in their transformation into 

 non-cihated or glandular cells (figs. 8, 11). In these figures it 

 can well be seen that the cilia never pass through the canaliculi, 

 but through the axis of the rods themselves. 



The intestinal cell has been considered by some to have a 

 brush border, and there is much diversity of opinion in regard 

 to the relation between the cilia and the hairs of the supposed 

 brush border. Vignon ('00) found, in the intestine of Chirono- 

 mus larvae, that the ciha are attached to the free extremities 

 of the hairs of the brush border, and believes that there is no 

 genetic connection between these two structures, whereas Pre- 

 nant ('97-' 99) and Holmgren ('03) assert that the hairs of the 

 brush border are nothing but atrophied cilia. According to 

 Gurwitsch ('01), there exists no relation, either genetic or ana- 

 tomic, between the cilia and the hairs, the former passing inde- 

 pendently through the spaces between the latter. 



2. Relation between the cilia and the brush border. Of the cili- 

 ated epithelia studied, I have found cells with brush borders in 



