THE CALCIFEROUS GLANDS OF EARTHWORMS. 
465 
and sometimes throughout a relatively large region entirely disintegrated. A certain 
number of the cells are ciliated, especially those towards or at the free edge of the 
lamellae (fig. 6). 
The duct by which the interior of the gland communicates 'with the oesophageal 
lumen is narrow and short, lined with low columnar epithelium which is heavily 
ciliated. Rodlets, but not distinct cilia, appear as a layer on the lining epithelium 
of the oesophageal lumen for a short distance on each side of the entry of the ducts. 
The Glands in the Genus Eutyphceus (Figs. 7-10). 
The Glands as seen in Dissection. 
If a large species of Eutyphceus , such as E. gigas, be taken for dissection, it will 
be seen that the region of the alimentary canal corresponding to segment xii is slightly 
swollen, but not sharply delimited from the rest of the tube. On opening this 
portion by a median longitudinal incision a number of transverse lamellae will come 
into view on each side (fig. 7) in such a way as to leave a median vertical channel in 
the middle ; their dorsal edges are not attached to the inner face of the oesophagus, 
so that a T-shaped lumen is visible in a transverse section of the tube. The lamellae 
of either side may be spoken of as constituting a gland ; the pair of glands are thus 
contained within the gut — not appendages which project outwards from the gut. 
The individual lamellae cannot be freely separated from each other, since they 
are attached to and held together by a vertical wall along their inner borders ; this 
wall partitions off the interlamellar clefts from the central lumen of the oesophagus, 
which thus forms a median corridor ; the interlamellar clefts are, however, open 
above. In addition, a large blood-vessel may be seen running longitudinally along 
the upper edge of the vertical wall, or, in other words, along the upper and inner 
edge of the gland on each side. 
Structure o f the Glands as studied in Sections. 
Sections taken in various directions confirm the above description of the glands as 
consisting of a large number of vertical transverse lamellae on each side of a central 
lumen, a vertical longitudinal wall on each side separating off the lamellae from the 
central lumen, and a system of included interlamellar spaces open above {cf. fig. 8). 
In addition, it is seen that a number of the lamellae are incomplete, attached to the 
vertical partition and not reaching outwards as far as the lateral wall of the gut ; 
or attached to the lateral wall and not reaching the vertical partition. Neighbour- 
ing lamellae may sometimes be united by synapticula ; or a lamella may split into 
two, the two reuniting at some distance and thus enclosing a long slit-like space. 
The lamellae and vertical wall consist of a double layer of epithelium ; the muscular 
coat of the oesophageal wall surrounds the whole, and sends no extensions into the 
lamellae or vertical wall. 
