PHARYNGEAL GLAND OF THE EARTHWORM 45 
of the skin (PI. 3, fig. 10, mw. ¢.). In these sections the mucin 
is stained red, while the rest of the tissue stains in all shades of 
blue. 
(b) Conductive or musculo-vascular portion. 
As one follows them continuously from the deep glandular 
portion to the muscular or central region of the pharyngeal 
bulb, the glandular cells gradually change their structure (PI. 8, 
fig. 5, m. gl.). They become smaller, their basophile protoplasm 
becomes more and more reduced, while the clear protoplasm, 
filled with granules of mucin, rapidly increases in quantity. 
These granular mucinous portions of the cells fuse together 
and form wide strands of mucin, the granules of which are 
regularly distributed im a multitude of sinuous rows (mw.). 
Nearer to the pharynx several small cells with basophile 
protoplasm may still be found embedded in this mucin, but 
usually one finds on the surface of these mucin ducts a 
few small nuclei (Pl. 3, fig. 6, d. mu.) filled with chromatic 
granules. These large mucin ducts subdivide and_ pass 
sradually into smaller ducts which are interlaced with the 
muscle fibres (m.) and blood-vessels (v.) This gradual passage of 
the glandular salivary cells into the salivary or mucin ducts was 
misinterpreted by Stephenson for a gradual transformation of 
his ‘ chromophile ’ cells into fibrillar or reticular packing tissue 
(‘ Fillegewebe ’). It is also evident that the connective tissue 
described by Stephenson is no other than the above-described 
salivary ducts containing precipitated and stained mucin. 
The musculo-vascular portion of the pharyngeal gland thus 
contains : (1) very strongly developed muscle fibres, (2) blood- 
vessels, and (3) salivary ducts filled with mucin. 
To these we can now add: (4) nerve fibres, (5) nephrocytes 
or excretory cells similar to the yellow cells of the alimentary 
canal, and, finally, (6) cells with bacteroids or crystals of 
uric acid (Pl. 3, figs. 2and 9, wr.). Concerning the nature of the 
last two elements I have more to say in the supplementary notes 
to this paper (p. 54). 
