New Monogenetic Trematodes, II — Yamaguti 
433 
cotylophore' which is 2. 4-4.2 mm long by 2.8- 
3.8 mm wide and extends on the ventral side 
from behind the posterior end of the ovary to 
a considerable distance back of the posterior 
end of the body proper. In the type this cotylo- 
phore begins in the midventral region at the 
level of the junction of the middle with the 
posterior third of the entire body with a smooth 
semicircular fold 1.2 mm wide which is fol- 
lowed by a twisted, fan-shaped body fold 
fringed with a semicircular row of 18 or 19 
long-stalked clamps. For convenience of refer- 
ence the clamps are numbered from in front 
backwards; the first clamp next to the semi- 
circular fold is the smallest (about 0.2 mm in 
diameter), rather short-stalked, the 12th may 
be slightly out of the row of other clamps, the 
14th to 16th are the largest (up to 0.45 mm in 
diameter), with longer stalks, and the last 18th 
(19th in one paratype) attached to the right 
posterior end of the body proper is provided on 
the proximal anterior margin of its stalk with 
a blunt-conical or subcylindrical caudal appen- 
dage 0.15—0.16 mm long. This caudal appen- 
dage is armed in the type with a small guarded 
apical hook 35(i long and two dissimilar sub- 
apical hooks, one of which is 77|x long and 
guarded like the apical hook, but the other is 
simple, falcate and 37p long lineally. In the 
paratypes either the guarded subapical or the 
falcate hook is absent (see Fig. 7 C), so that the 
armature of this appendage is variable. Clamp 
skeleton 0.18-0.46 mm in diameter, consisting 
of an arcuate, perforated, median spring, and 
two pairs of curved lateral arms articulating 
with each other, of which the smaller pair 
articulates at the distal end with a small X- 
shaped accessory sclerite. 
Head end rounded; mouth aperture wide, 
subterminal; oral suckers paired, muscular, sep- 
tate, 53-81 X 65-93p; pharynx oval, weakly 
muscular, 1 1 6 X 98p in the type. Esophagus 
simple, 0. 5-0.7 mm long, bifurcating a little 
behind genital pore. It is not certain whether 
the intestinal limbs are confluent posteriorly or 
not ; there are wide anterolaterally directed 
diverticles on each side anteriorly (Fig. 7 D), 
the remaining greater part with few short inner, 
and numerous longer, subdivided, outer 
branches accompanied by vitellaria and pigment 
cells; posterior outer branches extending into 
basal portion of clamp stalks. 
Testes rounded, about 50 in total number, 
arranged in two zigzag longitudinal rows, one 
on each side of median line; anterior ones pre- 
ovarian, posterior ones para-ovarian, some be- 
tween ovarian limbs. Vas deferens straight or 
gently undulating in median field, surrounded 
at its distal end by prostate cells; no pars pro- 
statica differentiated. A distinct globular bulb 
of very fine muscle fibers is developed around 
the somewhat swollen distal end of the ejacula- 
tory duct. Cirrus represented by a cylindrical 
group of very fine acicular spines, enclosed 
basally in a crown of 18 hooks, which in turn 
is enclosed in the atrial bulb with thick walls 
of radial muscle fibers. The hooks are fused 
near the base, and their simple attenuated 
points are curved inwards. This thick-walled 
atrial bulb is 51-80p in outside diameter, and 
enclosed entirely in the genital atrium with a 
membranous wall. Genital pore midventral, 
immediately in front of the above mentioned 
thick-walled atrial bulb, 0.5-0. 7 mm from head 
end. 
Ovary inverted U-shaped, 2.35 mm long by 
0.4 mm wide as a whole in the type, enlarged 
at proximal end to an elongate compact mass, 
situated to right of median line in middle third 
of body. Genito-intestinal duct arising from 
germiduct just before the latter unites with the 
stem of the vitelline reservoir. Ootype postero- 
sinistral to this genital junction. Uterus proper 
alongside vas deferens, opening into genital 
atrium ventral to male duct. Mature eggs elon- 
gate oval, 0.25-0.26 X 0.11-0.15 mm, with a 
rigid filament at each pole; anterior filament 
0.19-0.26 mm long, posterior filament 0.12- 
0.2 mm long, slightly enlarged at tip. Genito- 
intestinal duct running straight obliquely for- 
ward and emptying into right intestinal limb, 
with distinct accompanying cells. Vaginae in- 
distinct in the type, but present on each side in 
form of a ventrosubmarginal longitudinal row 
of several rudimentary areolae just behind level 
of symmetrical excretory pores in one of the 
paratypes. Vitelline reservoir Y-shaped, with 
short arms. Excretory pores symmetrical, dorsal, 
submarginal at about level of genital pore or a 
little posterior to it. 
