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PACIFIC SCIENCE, Vol. XIX, January 1965 
Pharynx globular, 62-8 5 /a in diameter; pre- 
pharyngeal portion well differentiated from mus- 
cular pharynx. Ceca wide, with short inner and 
longer outer branches, terminating dorsal to 
opisthohaptor where the most medial branches 
appear to be united together. 
Testes oval, about 100/a long, almost sym- 
metrical, one on each side of median ovarian 
curvature. Vas deferens turning round the bulbus 
ejaculatorius and penetrating it at its posterior 
end, forming two dilatations, one immediately 
in front of the bulbus and the other immediately 
behind the bulbus, both serving as seminopro- 
static reservoirs, because they contain sperma- 
tozoa and prostatic granules secreted from the 
neighboring prostatic cells. Bulbus ejaculatorius 
75-110 X 57-80/x, containing abundant granules 
in wide space between its wall of circular mus- 
cles and the ejaculatory duct. Copulatory organ 
consisting of a well sclerotized, tubular, cirrus 
proper which is 30-45/a long, more or less flared 
at each end and provided sideways with a sclero- 
tized fold, and of a bundle of about 10, slightly 
curved, slender, accessory spines. To the base of 
the cirrus are attached special whirling muscle 
bundles merging into surrounding body paren- 
chyma, probably associated with movements of 
the cirrus; the cirrus and its accessory spines 
project backwards toward the ventral genital 
pore situated immediately in front of the uterine 
pore. 
Ovary 75-150 X 150-250/a, just postequa- 
torial; its greater proximal portion V-shaped, 
with its end more or less swollen and its right 
arm embracing right cecum. The germiduct aris- 
ing from the distal end of the ovary joins the 
common vitelline duct and the duct from the 
vaginal seminal receptacle medial to the swollen 
proximal end of the ovary; the fertilization canal 
describes a sigmoid curve and after being sur- 
rounded by shell glands of two different types 
leads into the uterus proper. The latter is funnel- 
shaped, with distinct epithelial lining, opening 
midventrally by a large rounded aperture behind 
male pore. Eggs mitral, 75-83/a long by 75-83/a 
wide in life, 95—100 X 80-95/a in mounted con- 
dition, with prominent posterior lateral ends, 
from one of which arises the fine filament. 
Vagina strongly sclerotized basally, opening 
ventrally medial to left intestinal limb. Recep- 
taculum seminis rounded, 40-60/a in diameter, 
enclosed in proximal portion of vagina. Vitel- 
laria co-extensive with intestine; transverse vitel- 
line duct equatorial. 
DISCUSSION: This monocotylid genus differs 
from any other members of the subfamily Mono- 
cotylinae by possessing two testes instead of one, 
although resembling Heterocotyle minima (Mac- 
Call urn, 1916) Price, 1938, in general anatomy. 
The generic name refers to this feature. 
Diploheterocotyla n. g. 
GENERIC DIAGNOSIS: Monocotylidae, Mono- 
cotylinae: No eye spots. Opisthohaptor divided 
by eight septa into eight muscular marginal 
loculi and nonmuscular central loculus, with 
one pair of anchors. Interlocular marginal book- 
lets hardly recognizable. No other sclerotized 
structures on opisthohaptor. Oral sucker sur- 
mounted anterodorsally by transversely elon- 
gated lobe. Pharynx strongly muscular, pre- 
ceded by special prepharyngeal structure. In- 
testinal limbs with side branches, terminating 
dorsal to opisthohaptor. Testes two, subsym- 
metrical behind ovary. Bulbus ejaculatorius well 
developed, with wide space filled with fine 
granules between its wall of circular muscles and 
the ejaculatory duct penetrating It. Copulatory 
organ consisting of a well sclerotized, tubular 
cirrus proper, and a bundle of slender accessory 
spines; male genital pore immediately in front 
of uterine pore. Ovary curved, immediately pre- 
testicular, embracing right intestinal limb. Uter- 
ine pore midventral, behind male pore; eggs 
mitral, filamented at one posterolateral end. 
Vitellaria co-extensive with intestine. Vagina 
present. Receptaculum seminis enclosed in va- 
gina. Parasitic on gills of elasmobranchs. 
TYPE SPECIES: D. dasyatis n. sp., on Dasyatis 
sp.; Hawaii. 
5. N eobaiiotrema mao mao n. g., n. sp. 
Fig. 5 
HABITAT: Gill of Abudefduf abdominalis 
(local name "maomao”); Hawaii. . 
holotype: U. S. Nat. Mus. Helm. Coll, S.Y. 
No. 5. 
DESCRIPTION (based on 25 whole mounts): 
Body very small, elongate, 0.23-0.44 mm long, 
up to 60—90/a wide in midregion. Opisthohaptor 
