New Monogenetic Trematodes from Hawaiian Fishes, II 1 
Satyu Yamaguti 
In this second report are described seven 
new species of monogenetic trematodes belong- 
ing to six new genera, two of which represent 
each a new subfamily. One of these two species 
seems to occur rather uncommonly on the 
Hawaiian flying Ashes; so far I have managed 
to collect only four specimens after a long 
search. Although the host of this worm is a 
pelagic Ash, its parasite fauna seems rather 
endemic in character, inasmuch as the mono- 
genetic and digenetic trematodes found on or 
in the Hawaiian flying Ashes are quite different 
from those occurring in the allied host species 
in the neighboring waters. This fact strongly 
suggests that the distribution of the Hawaiian 
flying Ashes is not very extensive. 
All the other new genera of Monogenea to 
be reported by me from Hawaii will be de- 
scribed in a monograph upon Hawaiian mono- 
genetic trematodes, so that the present report 
is the last of the series for new Hawaiian mono- 
genetic genera to be described in short articles. 
Thanks are due to all the institutions and 
persons concerned in my survey of Hawaiian 
trematodes, including the National Science 
Foundation, the University of Hawaii, my assis- 
tant, Mr. Shunya Kamegai, and my wife, Ikuko 
Yamaguti. 
The new species described herein are assigned 
to the following families and subfamilies: 
I. Capsalidae Baird, 1853 
Benedeniinae Johnston, 1931 
1. Pseudallobenedenia apharei n. g., n. sp. 
2. Pseudallobenedenia opakapaka n. sp. 
3. Lagenivaginopseudobenedenia etelis n. 
g., n. sp. 
II. Discocotylidae Price, 1936 
Opisthogyninae Unnithan, 1962 
4. Metopisthogyne sphyraenae n. g., n. sp. 
1 Contribution No. 248 from Hawaii Institute of 
Marine Biology, University of Hawaii, supported by 
a grant (GB-2992) from the National Science 
Foundation. Manuscript received May 3, 1965. 
III. Pterinotrematidae Bychowsky and Nagi- 
bina, 1959 
5. Pseudopterinotrema albulae n. g., n. sp. 
IV. Axinidae Unnithan, 1957 
Sibitrematinae n. subfam. 
6. Sibitrema poonui n. g., n. sp. 
Cypselurobranchitrematinae n. subfam. 
7. Cypselurobranchitrema spilonotopteri 
n. g., n. sp. 
1. Pseudallobenedenia apharei n. gen., n. sp. 
Fig. 1 
habitat: Gills of Aphareus rutilans; Hawaii. 
holotype: U. S. Nat. Mus. Helm. Coll., 
S. Y. No. 45. 
description (based on 21 whole mounts) : 
Body approximately fusiform, 2. 6-5. 3 mm 
long, with maximum width of 0.7-1. 9 mm at 
about testicular level. Posterior extremity of 
body proper attenuated to a flap covering opis- 
thohaptor dorsally. Opisthohaptor discoid, usu- 
ally projecting a little beyond posterior end of 
body proper, 0.43-0.8 mm longitudinally ex- 
cept for scalloped marginal membrane 20-80p 
wide, with a central pit 0.1-0.15 mm in diame- 
ter; on the concave ventral surface there are 
three pairs of anchors, but no deflnite septa or 
ridges, although several symmetrical radiating 
excretory vessels are seen bifurcating or not at 
their submarginal ends; anterior anchor 28-37p 
long from tip to posterior end, situated postero- 
lateral to central pit; two posterior anchors 
close together near posterolateral edge of opis- 
thohaptor; longer J -shaped medial one slender, 
1 8— 33pi long; shorter lateral one hook-shaped, 
with bifld root, l4-21p long. Prohaptors ellip- 
tical, saucer-shaped, 0.54-1.0 X 0.24—0.48 mm, 
connected dorsally by medianly incised frontal 
plate which never projects forward beyond the 
prohaptors. Mouth opening ventrally at level 
of posterior end of prohaptors, with one pair or 
two of eyespots dorsally. Pharynx muscular, in- 
cised anteriorly into Ave lobes, more or less 
419 
