302 
Florence Peebles. 
In what manner the eggs are extruded from the body is stili unsettled. 
It is possible that they are forced out through the mouth, or they may 
pass between the parenchyma cells through a temporary opening which 
closes immediately after the eggs are laid. At the time when these worms 
were collected the eggs were mature, but none were observed in the act 
of extruding the eggs. It is evident that they are fertihzed within the 
body, for various stages of maturation, fertilization, and the first seg- 
mentation spindle (fig. 5, o) have been found in cross-sections of the 
worms. 
The ovaries of Monochoerus Uneatus consist of two thin-walled sacs, 
extending along the body from the region of the bursa to the brain. These 
sacs unite in the middle of the body to form one farge sac which when 
distended, with eggs, occupies the entire region between the mouth and 
the bursa. 
The testes which are folHcular, also extend anteriorly to the level 
of the brain. The vasa deferentia broaden out into large coils in the 
region of the penis (fig. 7, vd). 
According to Löhner and Micoletzky, the genus Monochoerus is 
distinguished by the fact that the chitinous mouth-piece opens into the 
parenchyma, and not to the exterior as it does in Convoluta. As shown 
in the sagittal section in fig. 8, the mouth-piece of Monochoerus Uneatus 
opens into the parenchyma at some distance from the ventral surface 
of the body. In transverse section (fig. 5), it also shows no connection 
with the exterior. 
c) Kelation to other Acoela. 
It is evident that Monochoerus Uneatus and Monochoerus illardatus 
are closely related species. In order to compare them the foUowing tabu- 
lation of their chief characteristics has been made. 
