ee un ee ee 
en ee 
69 
Fig. 31. Schematie longitudinal section through the hinder extremity, not in 
but parallel to the median plane. 
R. the glandular tube into which the genital ducts dd’ open. 
Pg. the preanal gland. 
A. the anal cavity. 
B. the ceylindrical, blind-ending cavity penetrating into the organ 
that might be compared to a byssus-secreting apparatus. 
Fig. 32. Enlarged transverse section through the posterior extremity of the 
body, somewhat behind the spot where the schematie section re- 
presented in fig. 39 was taken (along the line xy in fig. 46). 
The superior and lateral portions are not represented in the figure. 
Rec. the rectum folded longitudinally. 
er. the strongly ciliated epithelium of the rectum. 
be. the bloodeorpuscles, enclosed between the folds of the rectum. 
dd. the medial 
d’d’. » lateral 
and the hermaphrodite gland into direct communication with the 
portions of the ducts that bring the pericardium 
glandular tubes A and R (cf. fig. 46). Genital products were 
observed inside these ducts. 
ce. the ciliated epithelium of these ducts, strongly folded and 
surrounded by a strong layer of circular muscles. 
ve. a vascular longitudinal ridge inside these ducts. 
RR’. the glandular tubes (nephridia) of fig. 46 just behind their 
point of junction into one tube. 
c. their internal cavity lined by a disintegrating epithelium. 
ge. the high, multicellular epithelium subjacent to the former, 
externally enclosed in 
m. the essentially circular muscular investment. 
N. the posterior (thickest) commissure between the pedal nerves. 
nn’. the lateral nerves. 
PG. the anterior portion of the pre-anal gland. 
I. the integument. 
F. the ventral slit inside of which are the ciliated folds of 
which the median one is the posterior continuation of the 
 foot-fold. 
M. the muscular investment of the body. 
Mb. Mb’. the special muscular development, superposed upon 
the muscular investment of the body, and still in direct con- 
nection with it, inside of which the canal B of fig. 31 pene- 
