76 
PACIFIC SCIENCE, VoL XIX, January 1965 
somewhat muscular sigmoid duct and leads into 
slightly winding pars prostatica 0. 2-0.5 mm long 
and provided with circular muscle fibers and a 
coat of prostatic cells; ejaculatory duct sigmoid, 
0.1-0.22 mm long, with a very thick coat of 
circular muscle fibers, with its anterior end 
usually turned back on itself to lead into cirrus 
pouch. Latter cylindrical, 0.12-0.26 mm long by 
30-5 5fi wide, with longitudinal muscles, project- 
ing into genital atrium which consists mainly 
of circular muscle fibers. Immediately outside 
this genital atrium and cirrus pouch there is a 
thick coat of accompanying cells. Common geni- 
tal pore on sinistroventral margin of body 0.35— 
0.8 mm from head end. 
Ovary 0.5-1.15 X 0.08-0.22 mm, occupying 
interintestinal field at anterior half of caudal 
third of body, consisting of multilobed proximal 
end situated posteriorly, a narrow tubular por- 
tion ascending medial to right intestinal limb, 
and a looped main portion situated anteriorly 
with distal end directed posteriad. Germiduct 
running straight backward from distal end of 
ovary, giving off narrow genito-intestinal duct 
just before joining vitelline reservoir; ootype 
just anterior to proximal lobe of ovary. Uterus 
midventral, finally running alongside muscular 
ejaculatory duct and cirrus pouch and opening 
into genital atrium. Eggs fusiform, 0.2-0.21 mm 
long, with rather rigid bipolar filament 0.18- 
0.28 mm long. Vagina provided with sphincter- 
like circular muscles, with wide midventral 
opening at a distance of 0.8-1.9 mm from head 
end. Accessory vaginal ducts arising sideways, 
one on each side of vagina, each provided with 
sphincter-like circular muscle fibers at the point 
where it turns backwards to join the transverse 
commissure between anastomosing anteriormost 
vitelline ducts of two sides; median vaginal duct 
proper arising from middle of base of vagina 
traceable some distance back of vagina, but its 
posterior termination not determined. Vitellaria 
co-extensive with intestine; vitelline reservoir 
Y-shaped, with long stem co-inciding with 
ovarian zone. 
DISCUSSION: This genus grossly agrees with 
Opisthogyne Unnithan, 1962, in general anat- 
omy, but differs in several important characters 
such as: ( 1 ) oblique body ridges, as observed in 
Opisthogyne and Gemmacaputia, are entirely 
absent; (2) marked asymmetry of opisthohap- 
tor; (3) subsessile clamps with asymmetrical 
lateral sclerites due to unequal development of 
capsule of one proximal quadrant, whereas pe- 
dunculate clamps are symmetrical in skeleton; 
(4) ovarian complex shifted far backward by 
enormous number of testes; (5) vaginal pore 
midventral instead of middorsal. These differ- 
ences, especially the asymmetrical opisthohaptor, 
the asymmetrical skeleton of subsessile clamps, 
and absence of oblique body ridges, are suffi- 
cient to justify the erection of a separate genus, 
for which Pseudopisthogyne is suggested in 
recognition of its marked resemblance to Opis- 
thogyne Unnithan, 1962. In Opisthogyne Unni- 
than states that the vaginal duct opens into the 
ootype, but this is obviously an error. 
Pseudopisthogyne n. g. 
GENERIC DIAGNOSIS: Discocotylidae, Opistho- 
gyninae: Body elongate, nearly symmetrical, 
without oblique body ridges posteriorly. Opis- 
thohaptor asymmetrical, with four larger sub- 
sessile clamps on pore side, and four smaller 
pedunculate clamps on antiporal side; larger 
clamp with asymmetrical basal and lateral scler- 
ites, smaller clamp with exactly or nearly sym- 
metrical lateral sclerites. Caudal appendage 
with three pairs of anchors, attached to posterior 
end of body between posteriormost clamps of 
two sides nearer to small clamp than to large 
clamp. Head blunt-pointed, with well-developed 
paired apical organs. Esophagus diverticulate 
posteriorly, bifurcating at level of vagina; in- 
testinal limbs not confluent posteriorly. Testes 
very numerous, preovarian; pars prostatica, ejac- 
ulatory duct, cirrus pouch and genital atrium 
well differentiated; cirrus unarmed. Common 
genital pore in esophageal zone, ventrosubmar- 
ginal. Ovary turned back on itself, posterior, 
with both ends directed backward. Eggs fusi- 
form, with bipolar filaments. Vagina midventral, 
far posterior to genital pore, with paired ac- 
cessory vaginal ducts, each of which is connected 
with the transverse commissure between the an- 
terior anastomosing vitelline ducts of the two 
sides, medain vaginal duct proper rudimentary. 
Vitellaria co-extensive with intestine; vitelline 
reservoir Y-shaped, in ovarian zone; anterior 
vitelline ducts containing sperm. Gill parasites 
of marine teleosts. 
