NTEGUMENT OF NECTURUS MACULOSUS 065 
On the granular glands (fig. 31), on the other hand, some fibers 
go directly to the muscle cells, ending in small round plates or 
bulb-like expansions (Huber and DeWitt, 98; Herrick and Cog- 
hill, ’98; Coghill, ’99; Esterly, 04), while other smaller fibers 
branch frequently over the surface of the muscular layer and then 
send small branching twigs between the contractile cells into the 
gland (fig. 30). These intraglandular endings probably represent 
interepithelial free nerve endings which supplied the granular 
epithelium when it existed as distinct cells before a muscular 
layer had developed. No perinuclear baskets of. nerve fibers, 
such as Hsterly (’04) has described for the poison glands of 
Plethodon, were observed. 
SUMMARY 
Epidermis 
1. In the epidermis the cells of the transitional layers, as well 
as those of the so-called germinative layer, multiply by mitosis. 
2. No basement membrane is present, but from their lower 
ends the cells of the germinative layer send out fine processes, 
which blend with underlying connective tissue of the dermis. 
3. Except upon the hands and feet the free surface of the cells 
of the epidermis is provided with a dense top-plate, the so-called 
cuticular margin. 
4. The cuticular margin is perpendicularly striated. The 
striations are interpreted as the walls of the closely packed 
tubular alveoli which make up this region. 
5. The cuticular margin is, at least in part, a secretion product. 
6. In molting, only the cells of the cuticular layer are cast. 
7. A true horny layer is found only on the hands and feet. 
8. Unicellular glands, commonly spoken of as club cells, are 
very abundant in the epidermis. Their exact function is un- 
known. There is some evidence to indicate that they discharge 
directly on the surface of the epidermis. 
9. Typical goblet cells are found around the lips, in the epi- 
thelium of the mouth, and within the gular fold. 
