absent, not only over the pharyngeal pocket but also in the zone 
immediately adjacent, which is due to the exclusively dorsal location 
of the roots of the intestinal coeca. The ovaries are likewise 
missing in the broad marginal zone where the body is rather thin. 
Both testes and ovaries are very large and the germination centre 
has in the latter a dorsal location. 
Both large seminal canals lie as usual ventrally and run their 
customary winding course directly caudalwards. Before they turn 
towards the median line in the region of 
the male copulatory organ, the musculature 
increases and soon becomes so thick that 
a false seminal vesicle is developed. The 
vesicle narrows off during its course 
toward the median line and becomes a 
constricted muscular duet which opens up 
into the slightly expanded rostral part of 
the ductus ejaculatorius. The development 
of the two lateral false seminal vesicles 
is not so pronounced as in Discostylochus, 
and this faet is striking proof that false 
seminal vesicles originate only through 
local inerease of the musculature of the 
large seminal canals. In Leptostylochus it 
is, as a matter of faet, impossible to set 
a distinet proximal limit for the seminal 
vesicles. Their muscularis is compact with 
a nucleated zone that forms its outer 
envelope. 
The male and female copulatory organs are close to each other 
and the genital pores (text-fig. 11) are near the posterior end of 
the pharyngeal pocket. 
Ductus ejaculatorius (text-fig. 12, de.) is slightly expanded in 
its proximal end, where the two efferent duets from the seminal 
vesicles enter it. The first-named duet is short, and located at 
first underneath the prostate vesicle. Its thick muscular envelope 
fuses further distalwards with the muscularis of the duet of the 
prostate vesicle. The two epithelial tubes, on the other hånd do 
not fuse until near the „apex penis“. 
Text-fig. 11. 
Leptostylochus elongatus. 
Lang’s gladular vesicle (Lv), 
sexual pores, hinder parts of 
uteri (u) and pharynx in ven- 
tral aspect. The interupted 
lines indicate the shell giands. 
21 X. 
