H. Kobayashi 
401 
The distal part of the ductus ejaculatorius and the distal part of the female 
duct are surrounded by several longitudinal parenchyma muscles, forming a 
cirrus-pouch-like organ. 
The ovary lies posterior to the posterior testis. It is round and is smaller 
than the testes, its diameter feeing 0-35 mm. The well-developed shell-gland 
is situated posterior to the ovary. Laurer’s canal opens dorsallv. The recepta- 
culum seminis is lacking. The vitellaria are long and slender, running along 
the posterior intestinal caeca. They extend from the level of ovary to within 
8 mm. of the posterior end of the body. The loops of the uterus lie between 
the posterior intestinal caeca and extend backwards almost to the anterior 
end of the unpaired part of the excretory vesicle. There is no distinct vagina, 
the whole length of the uterine duct being provided with a cuticular wall. 
No perfectly formed eggs were found in the specimen under my observation. 
(19) Distomum sp. from Muraenesox cinereus. 
This species seems to belong to the Accacoeliinae, Hemiuridae, and may, 
perhaps, be new; but as I have only one damaged specimen I content myself 
with its description, and leave its species undetermined. 
It measures 11 mm. in length and 5 mm. in breadth in the posterior part, 
and it narrows anteriorly, the anterior end being 2 mm. wide. Its general 
form is conical, showing a somewhat circular outline in transverse section. 
The posterior end terminates roundly. 
The cuticle shows remarkable closely set transverse foldings. Subcutaneous 
muscles well developed in the anterior part, but posteriorly they become 
weaker. 
The oral sucker lies subterminally, its length being 0-6 mm. The ventral 
sucker is situated about 1 mm. behind the oral, and is deeply invaginated. 
It is T2 mm. in its entire length. 
The pharynx continues directly into the oral sucker, its length and breadth 
both measure 0-8 mm. The oesophagus is longer than the pharynx and makes 
a dorsal bend, and then bifurcates into intestinal caeca, which form several 
turns and terminate near the posterior end of the body. At the place of the 
bifurcation the oesophagus has two anterior diverticula, which end blindly 
at the level slightly anterior to the pharynx. The diverticula seem to be 
homologous to the anterior ramus of the intestine in species previously 
described. 
The two testes lie slightly obliquely with respect to one another near the 
posterior border of the ventral sucker. They are slightly and irregularly 
sinuate; their lengths are respectively about 0*2 mm. and 0-25 mm. The 
vesicula seminalis lies at the anterior dorsal part of the ventral sucker; its 
outline is ellipsoidal and near its middle part a septum-like narrowing is 
present. The pars prostatica is well differentiated, the length being 1 mm. 
The wall of this part contains several nuclei which bulge into the lumen. 
The main portion of the wall is occupied by the terminal part of the prostate 
