H. Ivobayashi 
399 
2 mm. x 1-2 mm. At its anterior part a depression is present on the body 
surface, the genital atrium. A part of the cirrus-pouch-like organ protrudes 
into the atrium to form the genital papilla, at the apex of which the ductus 
hermaphroditicus opens. 
The ovary lies at the level between the fifth bend of the intestinal caeca, 
slightly to the left of the median plane. It is tubular, winding irregularly 
several times; it measures about 2*3 mm. x 0*15 mm. Its median end opens 
into a broad and short oviduct. Laurer's canal is present and opens dorsally, 
while the receptaculum seminis is lacking. The vitellaria are situated at the 
posterior part of the body around the ovary and between the intestinal caeca. 
The distal end of the glands passes over the intestinal caeca. They have a 
dendritic form, are finely branched, and, in the mature specimen, the left 
and right halves are barely distinguishable. The main branches are 5-6 in 
number; they are united with one another in the anterior median part and 
distally they divide into finer branches. The yolk duct arises at the anterior 
median part. It is short and soon forms a yolk reservoir. The shell-gland is 
diffuse and the glandular cells have long slender ducts. The uterus makes 
six loops and is situated between the two intestinal caeca; some parts pass 
over the caeca to the exterior and run at right angles to the longitudinal axis 
of the body. In each loop are found still smaller undulations, which are more 
numerous in the posterior portion. Around the uterus are certain glandular 
cells which have a similar appearance to the shell-glands, except that they 
are provided with a shorter duct. Distally the uterus runs directly over the 
dorsal border of the ventral sucker on the left side of the cirrus-pouch-like 
organ and is continuous with the vagina, which enters the cirrus-pouch-like 
organ. After making several windings it unites with the ductus ejaculatorius. 
The eggs are numerous, the size being 0-048-0*05 mm. x 0-023-0-025 mm. 
A distinct lid is present. 
It is clearly seen that this species has affinities with the Hemiuridae, 
especially to the group of Distomum clavatum. 
I have once found a very young specimen of this species in the gills of 
Pseudobagrus auranticus. The shape is ovoidal, the anterior end being rounded, 
while the posterior end is somewhat tapering. Its size is 0-35 mm. x 0-2 mm. 
The broadest part is the posterior third of the body. The oral sucker 
lies at the antero-ventral end, the diameter being 0-12 mm. The ventral 
sucker lies slightly posterior to the middle of the body, the diameter being 
0-18 mm. Between the suckers the cirrus-pouch-like organ lies, touching the 
oral sucker anteriorly and the ventral sucker posteriorly. Both testes lie 
directly postero-ventrally to the ventral sucker; their shape is ellipsoidal, 
and each measures 0-05 mm. in diameter. The ovary lies slightly posterior to 
the testes, between which it is transversely elongated in the median plane; 
its length is 0-03 mm. The vitellaria are seen as an irregular cell-mass, lying 
posteriorly to the ovary. 
It is very interesting to note that in the coelom of the host no mature 
