480 
PACIFIC SCIENCE, Vol. XIX, October 1965 
Ovary narrow, tubular, winding, arising at a 
distance of 4.2-10 mm from head end, but ter- 
minating at variable distances; in the type and 
one paratype the genital junction lies far ante- 
rior to the midbody, but far posterior to this 
point in the other two paratypes. Germiduct 
very short; seminal receptacle absent. Descend- 
ing uterine duct strongly winding, surrounded 
by shell gland cells and studded with yolk cells 
for a distance of about 0.4 mm in the type, a 
short descending portion directly following it 
also strongly winding and distended with sperm. 
At the extreme posterior end of the body the 
descending uterus turns back on itself between 
the two cecal ends; the distal portion of the 
uterus runs straight forward along with the 
vas deferens; eggs oval, 18-21 X 11-14 g. Vi t- 
ellarium narrow, tubular, extending from be- 
hind ovary to extreme posterior end of body. 
DISCUSSION: This genus differs from Nema- 
tobothrium van Beneden in the following points: 
( 1) free in host tissue; (2) ceca provided with 
well-developed gland cells at the beginning, 
terminating at posterior extremity; (3) testes 
paired, extending from behind genital junction 
to near anterior extremity; (4) ovary extend- 
ing in testicular region; (5) uterus descending 
to posterior extremity where it takes its final 
ascending course. 
Nematohothrioides n. gen. 
GENERIC DIAGNOSIS: Didymozoidae, Nema- 
tobothriinae. Complete hermaphrodite free in 
host tissue. Body narrow, long, almost uni- 
formly wide. Oral sucker larger than pharynx. 
Posterior end of esophagus and anteriormost 
portion of ceca surrounded by prominent gland- 
ular cells, ceca terminating at posterior end of 
body. Acetabulum absent. Testes juxtaposed. 
Genital pore ventral, close to pharynx. Ovary 
and vitellarium single, tubular, long, winding; 
former confined to testicular region, latter be- 
tween ovary and posterior extremity. Uterus 
first descending to posterior extremity where it 
takes its final ascending course. Parasitic in sub- 
cutaneous connective tissue of marine teleosts. 
TYPE SPECIES: N. kalikali n. sp., in subcu- 
taneous connective tissue of opercular region 
of Pristipomoides sieboldii; Hawaii. 
13. Neonematobothrium kawakawa 
n. gen., n. sp. 
Fig. 13 A-E 
HABITAT: Free in subcutaneous tissue of 
opercular region of Euthynnus yaito (local name 
"kawakawa” ) ; Hawaii. 
HOLOTYPE: U. S. Nat. Mus. Helm. Coll, S.Y. 
No. 31. 
DESCRIPTION (based on three whole mounts): 
Body flattened, slender, 32-48 mm long by 
0.07-0.65 mm wide (about 37 mm long by 
70 /x wide in the type), tapered anteriorly to a 
sharp point, but rounded at posterior extrem- 
ity. Cuticle smooth throughout. Oral sucker and 
pharynx rudimentary, 10-23 and 7-14 /x wide 
respectively. Esophagus simple and slender an- 
teriorly, but profusely diverticulate on each side 
and surrounded by numerous small glandular 
cells for its greater posterior part, bifurcating 
in the type at a distance of 16.7 mm from head 
end into two limbs of similar structure and of 
unequal length; each limb is continued back- 
ward into a strongly twisted, narrow, tubular 
cecum, which terminates near the posterior ex- 
tremity. No acetabulum. 
Testes two, narrow, strongly twisted, parallel 
to each other for the most part, but originating 
at different levels; posterior testis originating 
0.5 mm from tail end and anterior testis arising 
12.5 mm further anteriorly in the type; each 
passing imperceptibly into vas efferens. In the 
type one vas efferens is swollen (50 g across) 
before joining its fellow at a distance of 5 5 
mm behind anterior end of ovary, 8.8 mm from 
head end. Vas deferens winding forward in 
median field close to final ascending limb of 
uterus. Common genital pore almost midven- 
tral, shortly behind pharynx. 
Ovary narrow, twisted like testes, originating 
2 . 0-3. 7 mm posterior to head end just at the 
level where the proximal ascending uterus 
crosses the median line from the left to the 
right as in the type, or 1.1-2 .4 mm further be- 
hind this level. It extends backward in the type 
for about 17 mm, turning from side to side 
several times, terminating at a distance of 20.5 
mm from anterior extremity, where it joins 
the anterior end of the ascending vitellarium. 
This genital junction is, therefore, posterior to 
the midbody in the type as well as in one sped- 
