STUDIES ON CILIATED CELLS 221 



into it. No centrosome and mitotic figure were seen in the 

 cells in question. 



2. Gills of Anodonta. The epithelium consists of ciliated and 

 non-ciliated cells. Of the ciliated cells I have studied lateral-cells 

 and corner-cells. Both these cell- varieties are provided with a 

 cuticle carrying long cilia, which, in fixed preparations, are curved 

 towards the external surface of the gill-torus, as noticed by 

 Engelmann ('80); this is especially well marked in the lateral- 

 cells. The behavior of the laj^er of basal corpuscles, of the 

 transparent zone and of the chondriocontes is analogous to that 

 described above for the foot of the same species (fig. 4). 



The layer of basal corpuscles, which seems to correspond to 

 the zone found by Wallengren ('05) below the cuticle, contains 

 basal corpuscles, in the shape and arrangement of which the 

 lateral- and corner-cells differ widely from each other. Viewed 

 from the surface (fig. 5 a), the lateral cells, each of which has a 

 regular rectangular outline, are arranged in stone-wall-like rows 

 running along the gill-torus. The basal corpuscles are spheri- 

 cal granules, which form parallel rows arranged in the direction 

 of the short diameter of the cell-border, as is the case with the 

 foot-epithelium of the same species. Engelmann ('80) has also 

 described such a linear arrangement of basal corpuscles; he 

 states that the lines are inclined about 45° to the longer margin 

 of the cell-border, but I could not confirm this. 



The corner-cells, separated from the series of lateral-cells by 

 two rows of non-ciliated cells, are closely apposed on their flat 

 faces, forming a series along the gill-torus (fig. 5 b); in surface 

 view of this type of cell two parallel lines, stained black by iron- 

 haematoxylin, run along the longer axis of the cell-border. T ese 

 lines, named by Engelmann bandelets ('Leistchen') serve for 

 the attachment of the cilia, and might conceivably be formed, 

 as the author suggests, by the fusion of basal corpuscles. 



3. The intestine of Anodonta {figs. 6-8, 16). The epithelium in 

 this region consists of ciliated, non-ciliated and glandular cells. 

 The first two of these are pro\dded with striated cuticular borders ; 

 the clear space between the striae in lateral view correspond 

 with pores seen in surface views; this suggests strongly that the 



