82 
PACIFIC SCIENCE, Vol. XIX, January 1965 
eral sclerites. Head blunt-pointed, with well- 
developed paired apical organs. Esophagus 
bifurcating at level of vagina; intestinal limbs 
not confluent posteriorly. Testes very numerous, 
preovarian; vas deferens winding and sur- 
rounded by numerous prostate-like gland cells 
in postvaginal median field; prostatic complex, 
muscular ejaculatory duct, cirrus pouch and 
genital atrium well differentiated. Cirrus un- 
armed. Common genital pore ventrosubmarginal, 
anterior. Ovary posterior, turned back on itself, 
with both ends directed backwards. Eggs fusi- 
form, with bipolar filaments. Vagina simple, 
surrounded by circular muscle fibers in form of 
a sphincter, with midventral opening far pos- 
terior to genital pore; paired accessory vaginal 
ducts connected with transverse commissure of 
anteriormost anastomosing vitelline ducts, me- 
dian vaginal duct proper rudimentary. Vitellaria 
co-extensive with intestine, confluent posteri- 
orly; vitelline reservoir Y-shaped, to left of 
ovary; anterior vitelline ducts containing sperm. 
Gill parasites of marine teleosts. 
TYPE SPECIES: P. lepidocybii n. sp. on Lepi- 
docybium flavobrunneum; Hawaii. 
13. Pseudodiscocotyla opakapaka n. g., n. sp. 
Fig. 14 
HABITAT: Gill of Pristipomoides microlepis 
(local name "opakapaka”) and Apbareus ruii- 
lans; Hawaii. 
holotype: U. S. Nat. Mus. Helm. Coll, S.Y. 
No. 13. 
DESCRIPTION (based on 20 whole mounts): 
Body tapering anteriorly, 1.6-2. 7 mm in length, 
with maximum width of 0.22-0.6 mm at pos- 
terior half of body. Opisthohaptor with a median 
pair of larval hooklets at posterior end, divided 
into symmetrical lobes, each bearing an oblique 
row of four subequal clamps; clamp skeleton 
0.1-0.18 mm wide, consisting of a dorsal and a 
ventral pair of slender, unjointed, lateral arms, 
a median spring with bifid ends, and a pair of 
incurved basal rods. Head truncate, 0.15-0.2 mm 
wide. Paired oral suckers septate, 40-70 X 
60-1 lOg. Pharynx pyriform, 30-60 X 30-45g. 
Esophagus short, bifurcating just behind bulbus 
cirri. Ceca with short inconspicuous diverticles, 
extending into opisthohaptor, terminating very 
close to each other near wide posterior sinus be- 
tween two lobes of opisthohaptor. 
Testes 50-100 in number, occupying nearly 
whole postovarian intercecal field, divided into 
two lateral groups from behind ovary to level of I 
shell gland. Vas deferens winding in median | 
field dorsal to uterus. A stout ellipsoidal bulbus 
cirri about 75 X 60/x, provided subapically with 
a median group of 12 minute acicular spines 
and a pair of longer, very slender, lateral spicules, 
and apically with a certain number of slightly 
curved spines massed together; genital atrium 
with a crown of two alternating rows of minute 
spines, opening midventrally at a distance of 
0.17-0.35 mm from head end. 
Ovary bent back on itself, with its distal end 
directed backward, 100-170 X 60-1 12g, situ- 
ated on the right of median line just in front of 
middle of body. Germiduct arising from ovary 
soon gives off genito-intestinal duct opening 
into right intestine, and after joining the vitel- 
line reservoir continues its backward course be- 
tween the two submedian groups of testes, and 
then turns forward to be surrounded by shell 
gland cells. Uterus midventral, strongly dis- 
tended with eggs in some specimens. Eggs ellip- 
tical, 160-180 X 60— 70g, with a very long, fine, 
convoluted filament at each pole. On the ventro- 
lateral surface of the body at a distance of 0.27- 
0.45 mm from the head end there is a pair of 
oval symmetrical vaginae lined with corrugated 
cuticle, but their vaginal ducts could not be 
made out. Vitellaria commencing behind vagi- 
nae, and extending along whole length of in- 
testine except for its anteriormost portion; vitel- 
line reservoir Y-shaped, median, with its arms 
at level of ovary and its stem between two sub- 
median groups of testes. It is very remarkable 
that each arm is distended with sperm at its 
anterior end in the form of an oval sac. 
discussion: This genus resembles Discoco- 
tyle Diesing, 1850, in general anatomy, but dif- 
fers from it in the intestinal limbs not uniting 
posteriorly, in the heavily armed bulbus cirri 
and armed genital atrium, etc. It obviously be- 
longs to Discocotylidae Price, 1936, but cannot 
be assigned to any known subfamilies, hence a 
new subfamily is proposed for its reception. 
Pseudodiscotylinae n. subf. 
SUBFAMILY DIAGNOSIS: Discocotylidae. Ter- 
minal anchor -bearing lappet absent. Haptoral 
