ALIMENTARY CANAL, ETC., OF AMIURUS CATUS. 393 



and permits a view of the large oval nucleus placed in the centre of 

 the cell. In the lower columnar layers they are of smaller size 

 becoming more so towards the base, where one can easily observe 

 their differentiation from the surrounding cells. The reticulation is 

 at first fine and delicate, but becomes coarser and more marked as 

 the cell increases in size and thrust upward. 



These cells have been described in other fishes under the name of 

 beaker cells. I have prefered to use the term ' slime cells,' some- 

 times employed in referring to them. They do not conduct them- 

 selves towards reagents or staining fluids in the same manner as 

 beaker cells, from which they differ in shape. In no portion of the 

 alimentary tract does the beaker cell show a reticulation in its 

 mucigenous portion, nor does it stain generally with Bismarck brown 

 or hematoxylon any more deeply than do the surrounding cells. 

 The beaker cell again, it is quite probable, is simply a degradation 

 of the ordinary surface cylinder cell, while the slime cells show a 

 gradual growth and differentiation from those of the deeper epithelial 

 layers. The beaker cells and the slime cells must be regarded as 

 two distinct kinds of cells producing secretions, which probably are 

 chemically different. 



The other kind of cells referred to as present in the epithelial 

 layers of the membrane is known under the names of slime cells, 

 club or clavate cells. They are found in the outer skin also more 

 highly developed, and of a slightly larger size than in the membrane 

 of the mouth. 



These clavate cells are confined to the deeper epithelial layers 

 touching with their rounded heads the layers of flattened epithelium. 

 They are shaped exactly like a club, the larger ends rather blunt, 

 while the neck or handle tapers away into a fine thread-like continua- 

 tion, which I have traced to the base of the epithelial stratum. 

 (Fig. 1). The structure is provided with a distinct wall, and con- 

 tains in it two materially different fluid substances. That filling the 

 greater part of the head is strongly light refracting and contains, 

 situated toward the base of the cell, one or more rounded or oval 

 bodies provided with radiating strands which have been termed the 

 nuclei. They may sometimes be found in the fluid which fills the 

 neck of the cells, and are provided with nucleoli. These nuclear 

 bodies stain slightly in Bismarck brown, much more so than the sub- 

 stance of the neck which lines the walls of the head for some dis- 



