154 BULLETIN OF THE 
transverse sections at short intervals (Figs. 31-44). The general form 
of the tube may also be seen in the optical section represented in 
Figure 8. 
The cesophagus varies from 0.75 to 1.5 mm. in length, being from #5 
to sly of the total length of the worm. The loop which occurs near its 
posterior termination measures from 50 to 100 yp in length, and from 20 
to 30 1 in width. It lies nearly in the sagittal plane, and ventral to 
the general course of the wsophageal tube. The absolute uniformity of 
its occurrence and the normal appearance of the adjoining intestinal 
cells preclude the idea that this is an accidental fold. It must be 
regarded as a normal yet very curious feature of the esophagus. 
6. Intestine. 
The intestinal cells, which, as has been shown, are first encountered on 
the esophageal cell just behind the partition, are four in number at 
the point where the intestinal cavity is formed and the csophagus 
opens into it. These four however clearly constitute two pairs which 
are unlike (Fig. 37). The contents of one pair is a coarsely granular 
plasma, whereas that of the other pair is finer. The first remains un- 
stained in hematoxylin, but takes up enough hydrochloric acid car- 
mine to give the plasma a reddish tinge. The reverse is true of the 
other pair of cells. Occasionally the granules in the first pair of cells 
become very coarse, and then appear like excretory secretions. As 
already mentioned, there are no transverse partitions dividing the cell 
(Fig. 52), although a very large number of nuclei are present, usually 
several in each section (Fig. 39). Only two of the four cells are repre- 
sented in Figure 52, which is a surface view. The differences in the 
character of the nuclei are well shown in the figure. 
The walls of the intestinal cells are very strong, perhaps even cuticu- 
lar, since they remain intact long after the cell contents have been 
completely macerated out. There is however, no special chitinous lin- 
ing for the intestine, such as Birger has figured (’91, Taf. XX XVIII. 
Figs. 25, 29). This appearance is probably due to the partly macer- 
ated and detached membranes of the adjacent cells. . 
The portion of the intestine bounded by four cells is relatively short. 
One of the finely granular cells! dwindles down to a point (Fig. 45) 
and a new one takes its place. This pushes itself obliquely under the 
adjacent coarsely granular cell on one side, so that the latter is excluded 
1 Owing to a break in the series figured, I am unable to state positively which 
one of the original four is the first to disappear. 
