Fig. 4. Fig. 3. Secreting tube, longi- 
tudinal section. ZENKER’S fluid, 
Bronpi. 270/,. U. ©. Unripe cells. 
: J R. C. ripe cells. 
St Fig. 4. Preparation according 
REIT TAS Nae to EHRLICH-BETHE. Nerve plexus. 
& 600/,- 
are generally situated at the 
base of the cells. The epi- 
thelium of the large central 
duct is altogether different 
from that of the secreting 
tubes and has no secretory 
function. It is an ordi- 
nary columnar epithelium, 
the cells generally having 
smaller dimensions than the 
secretory. The protoplasm 
stains dark red with Bıonprs fluid and is without any granulation 
(Fig. 2). The nuclei are, as in the secretory epithelium, situated 
at the base of the cells. In the places where the secreting tubes 
open into the central duct, the change from secretory into ordi- 
nary columnar epithelium is abrupt (Fig. 2), the transition being 
in a single cell (Fig. 2). ‚The nerves follow the connective tissue 
septa, and from the thinnest of these, single nerves will be found 
to branch off amongst the cells, and, as far as I have been able 
to ascertain, end free (Fig. 4). The general structure of the poison 
gland of Heloderma is, as well as in poison glands of Ophidiae, that 
of a tubular gland, but the lobular arrangement met with in Helo- 
derma seems so far to be peculiar to this species. The submaxillary 
