Marshall and Sever in;—Anatomy of Ranantra fusca. 489 
posterior one, lying witldn the fourth segment, which is much 
thinner and is thrown into longitudinal folds. (PL XXXIY, 
Fig. 5.) The anterior portion is laterally compressed and appears 
two or three times as wide from a lateral as from a dorsal view. 
The stomach has somewhat the appearance of being spirally 
coiled; this appearance is given to it by indentations arranged 
in part alternately on either side. The entire surface when 
examined with a lens has a roughened appearance, due to small 
papillae-like outfoldings which are very close together and cover 
the entire surface. In sectioning this part of the alimentary 
tract the layer of epithelial cells is found to he very much folded 
and it is the outpushing of these folds that causes the roughening 
of the surface. The epithelial cells are different from those of 
the oesophagus in that they have a general appearance of secre¬ 
tory cells and stain darker. The folding of the epithelial layer 
is characteristic for the entire mid-intestine and is found else¬ 
where in the canal, only in the posterior end of the oesophagus 
and here hut slightly. The two muscle layers are present, the 
inner circular one has the fibres arranged in little groups and 
not in bands, as in the oesophagus. The posterior narrower 
part of the mid-intestine has the same external appearance as 
the anterior part, there being, however, a very abrupt decrease 
in the diameter of the canal where the two parts join. The 
folding of the epithelial cells is here not quite so marked as in 
the preceding part; the cells have the same appearance through¬ 
out the entire mid-intestine. Towards the posterior end of this 
section of the alimentary canal the circular muscles increase 
considerably in number, making this layer much thicker here 
than at any other part of the mid-intestine. 
The next section, the hind-intestine, is easily separable into 
a thin anterior portion, the ileum, and a thicker posterior part, 
the rectum. At its anterior end, the ileum receives the Mal¬ 
pighian tubes and their entrance marks the boundary between 
mid- and hind-intestine. The thickness of the two divisions is 
about the same. The roughened external appearance is also 
missing, and the folding of the epithelial layer disappears rather 
abruptly with the ending of the mid-intestine. Histologically, 
there is a marked difference between^ this and the preceding 
division. The external muscular layers are both present, but 
very slightly developed; internally a thin cuticle is present. 
The epithelial cells show towards their free ends a marked longi- 
