68 
and their diverticula, united posteriorly; trans- 
verse vitelline duct and shell gland immediately 
preovarian. Gill parasites of marine teleosts. 
TYPE SPECIES: P. carangis n. sp., on Caranx 
lugubris; C. sexfasciatus, and Myripristis berndti; 
Hawaii. 
7. Naso branchitrema pacificum n. g., n. sp. 
Fig. 7 
HABITAT: Gills of Naso h exacanthus (type 
host), Naso lituratus , and N. brevirostris; Ha- 
waii. 
holotype: U. S. Nat. Mus. Helm. Coll, S.Y. 
No. 7. 
DESCRIPTION (based on 12 whole mounts): 
Body elongate subcylindrical, slightly tapering 
anteriorly, 0.95-1.5 mm long, 0.11-0.26 mm 
wide at level of testis. Opisthohaptor 0.14-0.25 
mm wide, well set off from body proper, with 
two pairs of anchors, 3 separate bars, and sev- 
eral pairs of marginal booklets about 10 /x long 
at level of lateral prominences; dorsal anchors 
45-55 jm long lineally from tip of longer dorsal 
root to height of curve of blade, dorsal to lateral 
portion of ventral bar; ventral anchor 35-50 /*, 
long lineally from tip of base to height of curve 
of blade, with its obliquely flattened base articu- 
lating with ventral bar; of the three separate 
bars, the unpaired median dorsal 50-80/x long is 
constricted at middle, each half swollen medially 
and resting on transverse dorsal ledge of sub- 
median bar, tapered laterally; submedian bars 
meeting in median line, 55-80/x long, each swol- 
len at medial portion bearing above mentioned 
transverse ledge. Head trapezoidal, 0.07-0.15 
mm wide at base, with several head organs along 
each lateral sloping margin; head glands well de- 
veloped laterally at level of pharynx. Two pairs 
of eye spots anterior to pharynx. Pharynx globu- 
lar, 27-80g in diameter. Esophagus practically 
absent. Ceca simple, terminating separately pos- 
terior to testis at about middle of posterior third 
of body. 
Testes oval, 0. 1-0.2 X 0.045-0.12 mm, situ- 
ated at posterior end of middle third of body. 
Vas deferens running forward by right side of 
ovary and then along medial side of right in- 
testinal limb, passing between copulatory organ 
and vagina, and describing N -shaped curve in 
right anterior intercecal area; ejaculatory duct 
PACIFIC SCIENCE, Vol. XIX, January 1965 
running backward alongside efferent duct of 
prostatic reservoir. Copulatory organ complex in 
structure; main portion consisting of C-shaped 
cirrus from which two winding tubules arise in 
opposite directions, one reaching to a ringlike 
independent tubular structure and the other 
looping around the distal portion of the cirrus 
which turns back on itself to open into the 
genital pore. The proximal portion of the cirrus 
is produced forward into a clawlike structure, 
but there is another wide cuticular tube arising 
from near origin of the two above mentioned 
tubules and terminating in a slight enlargement 
where the ejaculatory duct and the prostatic 
ducts empty into the cirrus. Prostatic reservoir 
elongate oval to elliptical, 40-75 X 25-50/x, be- 
hind intestinal bifurcation, with its descending 
duct running alongside descending ejaculatory 
duct and opening into base of cirrus. Genital 
pore nearly median, some distance posterior to 
intestinal bifurcation. 
Ovary heart-shaped or irregular in shape, 50- 
100 X 30—100/a, immediately pretesticular, with 
shell gland complex in front. Vagina represented 
by a well cuticularized undulating, probably non- 
functional, tubule about 50 jm long and lying 
obliquely posterodextral to the copulatory organ. 
It is not certain whether it opens outside ven- 
trally or not. Vaginal duct narrow, descending 
from proximal end of vagina toward shell gland 
complex. No seminal receptacle. Shrunken egg 
observed in utero is about 80 /x long, produced 
backward into a rigid filament. Viteliaria co- 
extensive with Intestine; transverse vitelline duct 
in front of shell gland complex. 
DISCUSSION: This genus is characterized by 
the possession of three separate haptoral bars and 
a very complex copulatory organ. From the struc- 
ture of the haptoral apparatus there Is no doubt 
that it belongs to the Diplectanidae Bychowsky, 
1957, but differs from any of the known genera 
of this family by the absence of adhesive plaques 
or squamodiscs. It is defined as follows: 
Naso branchitrema n. g. 
GENERIC DIAGNOSIS: Diplectanidae without 
adhesive plaques or squamodiscs. Body elongate, 
subcylindrical, very small. Opisthohaptor well 
marked off from body proper, with two pairs of 
anchors and three separate haptoral bars, of 
