48 Wisconsin Academy of Sciences, Arts and Letters . 
are of various forms and dimensions according to their posi¬ 
tion. They are usually elongated, and more or less rounded 
toward their free ends. Toward the basal end of the cells, the 
cytoplasm shows in many places a distinct longitudinal stria- 
tion(Figs. 10 and 11, Is), more noticeable in some sections 
than in others; the cells, especially at the free ends, are partially 
filled with globules, which stain a bluish color with haematoxy- 
lin. These globules are not uniformly distributed throughout 
the cell; they usually decrease in number toward the basal end. 
Here and there, however, there are cells in which even the ba¬ 
sal portion is crowded with globules. Each epithelial cell con¬ 
tains a single spherical or ovoid nucleus, which contains a small 
number (one to six) of nucleoli. Here and there, young cells, 
each containing a small nucleus, are wedged in between older 
ones. Clustered together just inside of the basement membrane, 
between some of the epithelial cells, are small groups of from 
one to six or more regenerating cells (Eig. 10, rc ). We were 
unable to find any globules in the regenerating cells, but the 
cytoplasm stains more lightly than in the cells of the regular 
epithelium. The nuclei of these regenerating cells are smaller 
and stain more deeply with haematoxylin than do the nuclei 
of the long, cylindrical epithelial cells. 
The basement membrane, upon which rests the epithelium, 
is covered with a layer of circular muscles; these are abundant, 
especially at the inner end of the transverse folds. Outside of 
the circular muscles are the longitudinal, which, in an external 
view, appear as longitudinal fibers running parallel to one an¬ 
other. From these, branches are given off, which pass into 
the transverse folds of the mid-intestine. In a longitudinal 
section we were unable to ascertain with certainty the attach¬ 
ment of these branches. The longitudinal muscles extend pos¬ 
teriorly between the Malpighian tubules, and some continue as 
the external longitudinal muscles of the ileum. 
Malpighian Tubules :—A transverse section through the di 
gestive canal at the entrance of the Malpighian tubules shows 
that each opens separately, and that they do not all enter the 
mid-intestine in the same plane. Anteriorly and posteriorly 
to their entrance, the epithelial cells of the mid-intestine be^ 
