19 
of each of these three tielcls present a more or less exact symmetiy. 
The esophagus is more or less surrounded by certain structures, which 
will be described farther on. 
Chyle-intestine . — The ch}de-intestine or midgut (fig. 13) is of nearly 
uniform diameter and runs straight from the posterior end of the 
esophagus to the anterior end of the rectum. Focusing upon the 
ch}de-intestine through the body wall, one distinctly sees the bases of 
the intestinal cells; the}" are about in diameter and arranged much 
like the cells of a honey-comb. 
Viewed in transverse section the ch}"le-intestine is seen to be at first 
somewhat compressed laterally, then it becomes rather quadrangular, 
Fig. 10. 
iOO y(jU 
Fig. 11. 
Fig. 10. — Enlarged view of the head, showing the central nervous system; the crossed condition of 
the fibers was quite evident in one specimen, but compared ^vith other specimens this point in 
the drawing is somewhat exaggerated and diagrammatic. 
Fig. 11. — Transverse section of head through region of the central nervous system. In addition to 
the characters described for fig. 5, note that instead of a bridge connecting the four longitu- 
dinal bands, there is a distinctly fibrillated structure which represents the central nervous 
system. 
near the esophagus, but farther caudad it becomes somewhat flattened 
dorso-ventrally, so that its lateral diameter is about 308/^ to a dorso- 
ventral diameter (closed lumen) of 202/t. The lumen is suppressed, or 
nearly so, and contains no food; the high, C5dinder-epithelial cells are 
about 9/^ broad; those near the median line are longer (in some cases 
attaining about 90 pi) than those near the sides (which may decrease to 
30yw); the nuclei of these cells are arranged near the distal end, namely 
away from the lumen, and measure about 6yw; the cells themselves con- 
tain numerous particles, apparently representing reserve food material; 
