New Monogenetic Trematodes, II — Yamaguti 
427 
coextensive with intestine, commencing a little 
behind vaginal pore and terminating at base of 
opisthohaptor ; vitelline reservoir Y-shaped, in 
ovarian zone. Vagina funnel-shaped, strongly 
muscular, sending out a short narrow duct on 
each side of its anterior end. This duct appears 
to be connected with the anterior end of the 
longitudinal vitelline duct of its own side, al- 
though no distinct connecting duct is seen. 
Vaginal pore middorsal, postbifurcal, provided 
with a conspicuous bulb of fine lamellar muscle 
fibers, situated at a distance of 1.2-2.25 mm 
from head end. 
discussion: This genus differs markedly from 
Opisthogyne Unnithan, 1962, in the distribu- 
tion of the testes. In Opisthogyne the testes are 
limited to the preovarian region, whereas in the 
present genus they are much more numerous 
and more extensive. The V-shaped ridges charac- 
teristic of Opisthogyne and Gemmacaputia Tri- 
pathi, 1959, are absent in the posterior part of 
the body in the present genus. 
Met opisthogyne n. gen. 
generic diagnosis: Discocotylidae, Opis- 
thogyninae. Body symmetrical, elongate, with- 
out V-shaped ridges posteriorly. Four pairs of 
similar clamps of Gastrocotyle type. Terminal 
lappet with three pairs of hooks. Esophagus 
long; intestine with side branches, terminating 
separately. Testes numerous, mainly preovarian, 
partly para- and postovarian. Ductus ejaculato- 
rius strongly muscular. Cirrus muscular, un- 
armed. Genital pore ventromarginal. Ovary 
tubular, folded back on itself in posterior half 
of body; eggs fusiform, with filament at each 
pole. Vitellaria coextensive with intestine. Vag- 
inal pore middorsal, immediately postbifurcal. 
Gill parasites of marine teleosts. 
type species: M. sphyraenae n. sp., on Sphy- 
raena helleri; Hawaii. 
5. Pseudopterinotrema alhulae n. g., n. sp. 
Fig. 5 
habitat: Gills of Albula vulpes ; Hawaii. 
hqlotype: U. S. Nat. Mus. Helm. Coll., 
S. Y. No. 49. 
description (based on 26 whole mounts) : 
Body slender, cylindrical, 1.75-2.4 mm in 
length exclusive of haptoral clamps, up to 4.5 
mm in length including clamps, 0.12-0.26 mm 
wide in ovariotesticular region. Opisthohaptor 
fan-shaped, asymmetrical, on posterior exten- 
sion of body proper, with nine pedunculate 
clamps. As numbered from the right end of the 
opisthohaptor of the type the first to the ninth 
clamp gave the following measurements, pre- 
senting different features respectively: 
(1) First clamp 0.18 mm long, divided into 
a caudal appendage bearing a pair of large sub- 
apical anchors 37-48p long and two more, very 
small, apical hooklets 9-1 5 p long, and a shorter 
clamp than others. This clamp consists of two 
opposing valves fringed on each side with 
about a dozen curved spines and supported by 
comparatively short stout sclerites. 
(2) Second clamp arising from common 
trunk with first, 0.25 mm long, consisting of 
a slender stalk about 0.2 mm long, and pro- 
vided on each side with membranous fringe 
supported by a row of about a dozen acicular 
spines and a single axial sclerite; apical clamp 
valve single, fringed with over a dozen curved 
spines. 
(3) Third clamp about 0.4 mm long from 
its basal two-valved sucker to tip of double 
terminal clamp valve; its stalk supported by two 
unequal axial sclerites, one of which articulates 
with the sclerite of the second clamp at the base, 
while the other slender one articulates with the 
stronger axial sclerite of the fourth clamp ; 
axial clamp valves pressed against each other. 
(4) Fourth clamp 0.38 mm long, similar in 
structure to the third, with double apical clamp 
valve, bearing at base a two-valved sucker on 
the right and a larval lappet on the left. This 
lappet is a plump rod-shaped lobe 25-40p long 
by 15-22p wide and bears two pairs of very 
small larval anchors 12-17jx long. 
(5) Fifth clamp 0.47 mm long from its 
basal sucker to apex which consists of two 
similar valves. 
(6) Sixth clamp 0.25 mm long, with double 
apical valve similar in structure to that of third. 
(7) Seventh clamp 0.23 mm long; terminal 
clamp valves symmetrical. 
(8) Eighth clamp about 0.18 mm long, with 
two separate apical valves and a common stalk 
supported by two parallel axial sclerites, of 
