Marshall—On the Anatomy of the Dragonfly. 769 
A study of a series of transverse sections through the ileum 
shows that very near the anterior end these large cells, as al¬ 
ready stated, first appear in a large area which is ventral in 
position. In most parts of the ileum the epithelial layer is 
thrown into six longitudinal folds which, in a few sections, are 
quite large ; this area of large cells does not show any such 
folding hut lies parallel to the layer of circular muscles (fig. 
27, stippled part) and occupies the place of one of the folds, 
there being, as shown in the figure, this area and five folds.. 
This arrangement continues for some distance, then the area 
of large cells ceases and its place is taken by a fold, the sixth, 
corresponding to the other five. Posterior to this come the 
other two areas of large cells, lateral, but a little ventral in 
position ; these do not occupy so definite a region as the single 
large area but each one is in reality a part of the regular 
folds (fig. 28, stippled part). This arrangement continues un¬ 
til the ileum decreases in diameter near its posterior end. 
At the anterior end of the ileum the longitudinal folds 
begin very abruptly and there is, but for 1 a short distance 
however, a greater number of circular muscles than at other 
parts. The folds are at first not very large; they then increase 
in size and, in the last third or half of the ileum, become still 
larger and so remain until, near its posterior end, the ileum 
decreases in diameter. In this last region the folds nearly 
touch, making the lumen small and very irregular in trans¬ 
verse section. Hear its posterior end the ileum becomes nar¬ 
row and at the beginning of this narrow region the longitudinal 
folds end. This narrow portion forms only a small part of 
the entire length of the ileum but in appearance is quite dis- 
distinct; viewed from the surface this region appears like a 
collar around the hind-intestine; it has a peculiar, somewhat 
inflated, appearance or, often there are several small, rather 
irregular swellings. In this same region there were often 
found other swellings of various sizes, irregular in position ex¬ 
cept that they were always located in the same part; these 
were due to abnormal, parasitic, growths. 
