A 
can PROCEEDINGS OF THE NATIONAL MUSEUM. 95 
The anterior or oral sucker is 0.15 millimeter in its antero-posterior 
diameter and 0.12 millimeter in its dorso-ventral diameter; the diam. 
| eter of the passage between its muscular walls 0.02 millimeter. The 
yalls of the pharynx are almost contiguous with those of the oral 
~ sucker. Its length is 0.12 and its depth 0.09 millimeter. The length of 
the ventral sucker is 0.12, and its depth 0.21, and the thickness of its 
walls 0.06 millimeter. The cesophagus is short, at first deflected, ven- 
trally, then divides in front of the ventral sucker. The two branches 
at first diverge, then turn back towards the constriction. In these see- 
tions they could not be traced into the posterior region of the body. 
The walls of the pharynx, and particularly of the intestinal erura, are 
ciliated. 
The greater part of the anterior division of the body is filled with 
what I interpret to be the vitelline glands. The latter also occupy the 
| anterior and ventral region of the posterior division of the body. A 
| folded portion which occupies a central position (Fig. 29, y) appears to 
~ answer to Molin’s ‘lembo roversato.” It contains many nucleated cells 
and would appear from its position and structure to be an organ 
for absorption. <A lobed body (Fig. 28, x) is situated in the anterior 
division near the constriction and towards the dorsal side. This-is 
evidently the “kugliger korper” of Von Linstow, mentioned in his anat- 
omy of Holostomum gracile. The lobes of this body are composed of 
minute cells which are about 0.004 millimeter in diameter. The irreg- 
ular cleft which in these sections marks the limits of the lateral borders 
extends almost to the constriction (Figs. 28-29). 
The reproductive organs, with the exception of a part of the vitel- 
laria, lie in the posterior division of the body. The extreme posterior 
end of the body consists of a muscular suctorial organ with thick walls. 
In the middle of the base of this organ the uterus terminates in a 
prominent papilla (Fig. 28, p). On the dorsal side of the body, imme- 
diately in front of the bursa, is the pyriform cirrus pouch, with a duet 
leading therefrom and emptying into the uterus about the base of the 
papilla (Fig. 28,c). There does not appear to be any cirrus and the 
pouch probably functions as an ejaculatory organ. In front of the 
cirrus pouch, and occupying a position about on the median line, is the 
posterior seminal receptacle. The testes are large, extending from 
near the base of the bursa to near the middle of the posterior division 
_ of the body, and taking up three-fourths of the dorso-ventral diameter. 
They reach the body-wall dorsally and laterally, but not ventrally. A 
vas deferens lies along the ventral side of the testes, between them and 
_ the uterus. The shell gland, together with a portion of the germ duct 
| and the main vitelline duct and the beginning of the uterus, lies between 
the two testicular lobes (Fig. 28). 
The ovary is single, lenticular, and lies in front of the testes, at about 
the middle point of the body. (Fig. 28 0.) It is inclined forward at 
its ventral end and backward at its dorsal end. Laterally it reaches 
gm 
’ 
