296 'Journal of Comparative Neurology and Psychology. 



The primitive pores are frequently in close proximity to the 

 lateral line canals and their branches, yet in no case has the writer 

 observed a connection between the two, and is consequently unable 

 to confirm the statement by Collinge (i,p. 512) that many of 

 the branches of the lateral line canal end in primitive pores. 

 Collinge (i, p. 510) expressly states that his material was in poor 

 condition for histological study and it is probable that herein lies 

 the explanation of his error. 



The epidermis consists of from twelve to fourteen layers of cells 

 which at the surface are of the squamous type. These change 

 gradually into the deeper lying low cuboidal cells and finally into 

 the columnar cells of the basal layer (Fig. 3). At the margin of 

 the pores, the epidermis becomes thinner and as it passes over into 

 the neck of the pore it is further reduced to four or five layers. 

 On the sides of the pore the superficial epithelial cells are elongated 

 and have finger-like processes, which project freely into its lumen 

 (Fig. 3, m.c). The processes do not extend into the lumen of 

 the pore at right angles to the surface of the epithelium, but slant 

 toward the opening of the pore. These cells, which may be 

 spoken of as marginal cells, stain similar to those in the deeper 

 layers of the epidermis. 



The bottom of the pore is covered by a single layer of epithelium, 

 which is composed of two entirely diflTerent types of cells (Fig. 3). 

 The cells of the first type (sup.c.) are the more numerous and re- 

 semble low columnar cells, excepting that in most instances they 

 present an oval or oblong profile with the nucleus well out toward 

 the distal end (Fig. 6). These cells lie frequently in close contact 

 and sometimes in small groups. Scattered among these cells at 

 more or less regular intervals are the cells which belong to the 

 second type (sen.c.) and which in profile appear much like inverted 

 Indian clubs (Fig. 6). The expanded portions of the cells are 

 mostly superficial to the cells of the first type, while the slender por- 

 tions lie between them. The distal extremities of these cells are 

 drawn out into slender conical processes which are quite unlike 

 the finger-like processes of the marginal cells in that they are more 

 slender and have no granules in them. The bases of these cells are 

 broadly expanded where they come in contact with the basement 

 membrane. Their nuclei are small and lie in the expanded distal 

 portions. The most striking peculiarities of these cells are their 

 form, deeply staining capacity and clear processes. Because of 



