80 
PACIFIC SCIENCE, Voi XIX, January 1965 
clamp, and its proximal outer quadrant is so 
much developed as to push the lateral and basal 
sclerites of its own side toward the apex of the 
clamp, thus causing asymmetry of the clamp 
skeleton; the lateral sclerites of the proximal 
outer quadrant showing a gentle sigmoid curve 
in contrast with opposite lateral sclerites. 
Head blunt pointed, 0.2-0.42 mm wide at 
level of ventral mouth aperture, with a pair of 
well-developed apical organs. Oral suckers ellip- 
tical, 0.06-0.11 X 0.1-0.18 mm, with a septum 
at middle. Pharynx not muscular, 40-90 X 30- 
70/a; esophagus distinctly diverticulate posteri- 
orly, 0.2-07 mm long, surrounded by pigment 
cells, bifurcating at level of vagina. Numerous 
outer intestinal branches extend outward through 
the very dense layer of vitellaria up to the very 
lateral margin of the body. In the postovarian 
area the intestinal limbs are close to each other 
and terminate near the extreme posterior end of 
the body. 
Testes rounded, 90-185 in number, occupying 
whole interintestinal field in posterior half of 
anterior third and entire middle third of body, 
between vas deferens coils and ovary, in two 
longitudinal rows anteriorly and four zigzag 
rows posteriorly. Vas deferens winding first be- 
tween two rows of anteriormost testes and then 
in postbifurcal interintestinal area, where it 
is surrounded by numerous prostate-like cells. 
From a little anterior to the vaginal pore extends 
forwards in the median field a slightly winding 
muscular pars prostatica 0.22-0.6 mm long by 
30-65/a wide and surrounded by numerous pro- 
state cells; it passes into the strongly muscular 
ejaculatory duct which is 0.1-0.25 mm long by 
30-60/a wide and usually turns back on itself at 
its anterior end to be continued into the cirrus. 
Cirrus simple, unarmed, enclosed in cylindrical, 
muscular, cirrus pouch. Latter 0.16-0.25 mm 
long, 40-60/x wide, provided with longitudinal 
muscle fibers, extending obliquely toward left 
margin of body. Genital atrium 93/a wide in the 
type, surrounded by accompanying cells, pro- 
vided with circular muscles, opening ventrosub- 
marginally at a distance of 0.44-1.0 mm from 
head end. 
Ovary longitudinally elongated, shaped like an 
8, situated in anterior half of caudal third of 
body, with both ends directed backwards, 0.9— 
2.3 X 0.12-0.3 mm; proximal part multilobu- 
lated in a rosette-shape, next ascending portion 
tubular, crossing descending distal portion dor- 
sally; descending distal portion winding back- 
ward medial to right intestinal limb and then 
medial to ascending tubular portion. Genito- 
intestinal duct provided with circular muscle 
fibers, arising from germiduct just in front of 
junction of germiduct with stem of vitelline 
reservoir, opening into right intestinal limb at 
level of distal end of ovary. Shell gland cells 
massed closely together anterior to rosette-shaped 
portion of ovary. Uterus midventral, opening 
into genital atrium alongside cirrus pouch on 
its posteroventral side. Eggs elliptical, 0.22-0.25 
mm long by 50 - 70 /a wide; bipolar filament 
rather rigid, 0.2-0.35 mm long. Vagina sur- 
rounded by lamellae of circular muscle fibers like 
a sphincter, opening midventrally at a distance 
of 0.95-2.2 mm from head end; paired acces- 
sory vaginal ducts arising sideways from base of 
vagina, first running transversely, turning back- 
ward at the point provided with sphincter-like 
circular muscle fibers, may be distended with 
sperm together with yolk cells before uniting 
with transverse commissure of anastomosing an- 
teriormost vitelline ducts; median vaginal duct 
proper traceable in median field for some dis- 
tance back of vagina, but its posterior termina- 
tion not determined. Vitellaria extending in 
lateral fields, commencing at level of vaginal 
pore, confluent in postovarian median field; vi- 
telline reservoir Y-shaped; longer right arm 
crossing swollen distal portion of ovary on its 
ventral side; stem long, descending on left side 
of terminal descending portion of ovary. 
discussion : This genus differs from Pseudo - 
pisthogyne only in the absence of the hook- 
bearing caudal appendage. It is defined as fol- 
lows: 
Pseudopisthogynopsis n. g. 
GENERIC DIAGNOSIS: Discocotylidae, Opis- 
thogyninae: Body elongate, nearly symmetrical, 
without oblique body ridges posteriorly. Hook- 
bearing caudal appendage absent. Opisthohaptor 
asymmetrical, with four larger subsessile damps 
on side of genital pore and four smaller peduncu- 
late damps on other side; larger damp with 
asymmetrical, basal and lateral sclerites, smaller 
clamps with exactly or nearly symmetrical lat- 
