220 S. SAGUCHI 



Small pieces of the materials were preserved either in Meves's 

 fluid or in sublimate-acetic mixture, the result ot which was in 

 most cases favorable for the study of minute structures. With 

 the former fluid it was passed through grades of alcohol, after 

 washing thoroughly in running water, to 96 per cent alcohol; 

 with the latter it was brought immediately into 70 per cent 

 alcohol with iodine and then through grades of alcohol. Im- 

 bedded in paraffine through chloroform. 



The sections were, for the most part, cut 4 /x thick and stained 

 on the slide. For staining I have mainly employed Heidenhain's 

 iron-haematoxyhn method, with or without counterstaining with 

 plasma-dyes. 



III. STRUCTURE OF CILIATED CELLS 

 A. DESCRIPTIONS OF MY OWN OBSERVATIONS 



1. The foot of Anodonta. The epithelium consists of a roAv of 

 columnar ciliated cells (figs. 1, 2), the distal ends of which are 

 bordered with a well-defined, relatively broad cuticle which 

 stains faintly with iron-haematoxylin. In profile it is noticed 

 that the cuticle is striated longitudinally, each stria appearing 

 to be continuous with a cilium, which is from six to seven dmes 

 as long as the height of the cuticle. Below the cuticle is a 

 narrow zone, consisting of a series of basal corpuscles, which 

 may be called 'layer of basal corpuscles' (fig. 2). These are 

 minute, oval bodies appearing, in surface view, as small granules 

 arranged in parallel rows, which are, in most cases, at right 

 angles to the larger side of the distal cell-end (fig. 3). Below 

 the layer of basal corpuscles is another zone of dense nature, 

 which stains more deeply with plasma-dyes. Through this zone, 

 which provisionally may be designated 'transparent zone,' fine 

 fibers pass vertically from the basal corpuscles towards "he cyto- 

 plasm proper, where they become lost to view. The cytoplasm 

 contains a large number of tortuous mitochondrial filaments, 

 stained black by iron-haematoxylin; they are mainly arranged 

 vertically and are accumulated especially in the upper portion 

 of the cell-body, under the transparent zone, without passing 



