WILLIAMS: BOOPHILUS ANNULATUS. 
329 
Before passing to the description of the ovary itself another 
structure which appears at this level should, be described. The 
paired shell glands are to be seen in section in both figs. 17 and 18, 
(pi. 21) sh. gl. They are much coiled, as the sections show, and 
empty into the sides of the neck of the uterus at a level anterior to 
that of the section — in fact just as soon as the uterus is separate 
from the receptaculum. 
The shell gland has about the same diameter throughout its 
length and the lumen is constant. The nuclei of the cells of this 
gland stain very deeply in Heidenhain’s haematoxylin. The muscle 
fibers which are inserted on the neck of the uterus have already 
been described. 
The ovary itself is a tube whose wall is made up of one or at 
most two layers of germinative cells. The turnings and shape of 
the ovary are difficult to describe, but a comparison of figs. 19 and 
20 (pi. 21) and the text figures A and B will aid the description. 
Beginning at the receptaculum, an upward arch results in elevating 
the portions of the ovary just back of the uterus above the level of 
diverticula Id and 3d of the alimentary canal and thus makes the 
ovary one of the organs just beneath the dorsal hypodermis in the 
midlength of the animal. 
Th^ attachments of the two main rows of the dorso-ventral 
muscle fibers are to be found both to the outside and to the inside 
of this part of the ovary since here the ovary flexes sharply toward 
the sides of the animal. There is also just behind this region a 
depression of the ovary toward the ventral side of the animal, 
and the two concavities thus produced permit diverticula 2a and 
2b of the alimentarv canal on one side of the midline, and 2c and 
%/ ' 
2d on the other side to pass over the ovary and so back to their 
downward bending at the posterior end of the animal (see text 
figure C, page 332). 
The next elevation of the ovary carries its sides, both right and 
left, over the returning ventral divisions of diverticula 2b and 2c 
and over the ventral branches of the Malpighian tubules. 
The posterior portion of each side of the ovary is pressed toward 
the dorsal wall by the increase in size of the renal sac. It extends 
forward again some distance over the posterior part of the renal 
sac and at this point is continuous with the opposite side. If the 
single ovary be formed from the fusion of the posterior ends of two 
