INTEGUMENT OF NECTURUS MACULOSUS 503 
not discharge, but passively protected the animal from its 
enemies by simply serving as reservoirs for a poison which is 
presumably irritating to mucous membranes. Prowazek (’01, 
p. 86) concludes that they must. produce an intercellular secretion 
which makes its way gradually toward the outer margin and 
protects the skin from microbic and other injuries. Schuberg 
(07 c), in his work on the corium of Siredon pisciformis, inci- 
dentally describes in a foot-note (p. 564) and figures (Taf. XX VIT, 
Fig. 2) a Leydig cell discharging freely on the surface. 
In Necturus little variation in the form or position of these 
cells was observed. ‘They usually remained in contact with the 
outer layer of the dermis, although occasionally they were slightly 
separated from it. In a very few instances they were spherical 
and situated high in the epidermis. 
In the series of sections already referred to (p. 501), in which 
the secretion was in the form of large granules, some evidences 
of discharge were obtained. Several cells were found which 
had apparently ruptured at the upper ends and their contents 
had reached the outside, by way of the intercellular spaces, 
pushing apart the epithelial cells. The secretion appeared in 
small mounds or was flattened on the surface of. the epidermis, 
and the collapsed club cells, containing only nuclei and remnants 
of a reticular network, presented a striking contrast to the plump, 
well-filled cells situated on either side of them. In other places 
small masses of the secretion appeared in the intercellular spaces 
above the tops of the cells, possibly indicative of an early stage 
in the process of emptying in which the cell’ contents had not 
yet forced a path to the exterior. This, however, may represent 
the normal activity of these glands, perhaps significant in relation 
to molting, the breaking through to the surface being an acci- 
dental occurrence. The conditions noted in this isolated series 
may have been due to some mechanical disturbance of the 
tissue before fixation, yet no other parts of the preparations 
presented any evidence of distortion or crushing. 
In view of the small number of observations made, it seems 
unwise to attempt to draw any very definite conclusion regarding 
the possible function of the club cells in Necturus, but their 
