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ANATOMY AND HISTOLOGY OF PLEUROCHAITA MOSELEYI. 493 
intestine here being much paler in colour than in the posterior half; but cells 
similar to those already described in the dorsal pouches are found scattered 
about. Unfortunately, the intestine in this region was not in a very fit condition 
for histological examination, but a curious arrangement of the muscular coats 
could be made out. Instead of being separated into two layers, a longitudinal 
and a circular, as is generally the case in the alimentary tract, there appeared 
to be a simple network of muscular fibres running in every direction, most of 
them, however, being arranged parallel with the long axis of the intestine, and 
at right angles to it, but forming only one distinguishable layer ; the fibres are 
of various diameters, anastomose with each other, and are frequently curled 
into spirals, as if this part of the intestine was capable of extension, and served 
rather as a store-house for the food, the most active part of the digestion taking 
place in the posterior half of the intestine, where there is a more abundant 
development of glandular epithelium and of specialised glands. The posterior 
half of the large imtestine, commencing from about the 76th segment, and 
extending to the anus, is very different in appearance to the anterior half, being 
of a brownish colour, and showing under the microscope an abundant develop- 
ment of epithelium and the ordinary muscular coats (Plate XX VI. fig. 12). 
The walls are thrown into a series of transverse folds, one to each segment. In 
last thirty segments of the body the intestine is quite smooth internally, with the 
exception of three folds, but otherwise does not differ in appearance, and can 
hardly be distinguished as a special rectal region. 
Plate XX VI. fig. 12 is a section through the intestine in the region of the 
“kidney-shaped glands,” to be described shortly. The outer layer is composed 
of a quantity of large cells filled with granules, answering to the so-called 
hepatic cells on the intestine of the earthworm, which have, it is perhaps hardly 
necessary to remark, no relation to any intestinal secretion, but are merely 
the cells lining the body cavity of the animal. Beneath these come the 
muscular layers; the middle transverse coat being the most strongly de- 
veloped, and divided up into compartments by septa of connective tissue ; 
below the epithelium is a thin longitudinal layer, which may be muscular, or 
composed of connective tissue only. 
From the 86th to the 101st segment or thereabouts, are a series of glandular 
bodies, in all fifteen pairs, which lie on the dorsal wall of the intestine, but are 
quite distinct from it, being separated by a layer of the granular cells already 
described as lining the perivisceral cavity in this region. Each of these glands 
is faintly divided into lobules by furrows running at right angles to the long 
axis of the gland, and is somewhat kidney-shaped in outline, opening into the 
alimentary canal by a short but distinct duct, situated on its under surface. 
In the region of these kidney-shaped glands the walls of the intestine are 
very vascular ; the vessels are of a brownish tint, and exceedingly conspicuous ; 
