Cestode Parasites — Yamaguti 
29 
segments and a large number of secondary 
segments. Scolex 1.7-2. 8 mm long, with lateral 
bothria opening at anterior and posterior ends; 
apical disc, often prominent at center, 0. 5-0.7 
mm in transverse diameter, incised laterally. 
Proglottides campanulate, especially in anterior 
ones, which are medianly notched both dorsally 
and ventrally; gravid proglottides wider than 
long, medianly notched, 0.2-0. 8 mm X 0.5- 
2.3 mm, with very prominent posterior border, 
always containing one set of reproductive organs 
unless pseudosegmented. 
Testes arranged in one layer in two sublateral 
medullary fields, 25-50 or more in number on 
each side, not confluent in median field. Cirrus 
pouch elongate pyriform, 0.07-0.2 mm in 
diameter, usually slightly oblique, with strong 
circular muscles; vas deferens coiled around 
anterior end of cirrus pouch. Cirrovaginal pore 
dorsomedian, near posterior end of proglottis. 
Ovary bipartite, divided laterally into several 
lobules, up to 0.3-0. 5 mm in transverse diam- 
eter, at median posterior end of proglottis. 
Uterus sigmoid; uterine sac opening ventrally, 
rounded, up to 0.12-0.28 mm in diameter when 
distended with eggs, situated near anterior end 
of proglottis, usually only slightly to either side 
of median line. Eggs elliptical, operculate, 54- 
68p X 3 3-3 8 p in balsam mounts. Vitelline 
follicles small, profusely distributed in entire 
cortical parenchyma except for median field, 
not continuous from one proglottis to the next; 
vitelline reservoir ovoid, situated behind ovary 
on the same side of the median line as the 
uterine pore. Vagina provided with sphincter 
just before joining ejaculatory duct. 
discussion: This species is characterized by 
the lateral bothria being open anteriorly and 
posteriorly, and in the proglottides being 
campanulate. It occurs commonly in istiophorid 
fishes widely distributed in the Atlantic, Pacific, 
and Indian oceans. 
PARABOTHRIOCEPHALIDAE Yamaguti, 1959 
5. Metabothriocephalus menpachi n. g., n. sp. 
Fig. 5 A-E 
habitat: Intestine of Myripristis argyromus 
(type host, local name "u’u” or "menpachi”), 
M. chryseres (local name "pau’u’u”) and M. 
berndti (local name same as that of type host) ; 
Hawaii. 
holotype : U. S. Nat. Mus. Helm. Coll., 
S. Y. No. 375. 
description (based on a fragmented type 
120 mm long by 2.4 mm wide and two para- 
types, each of which is broken into several frag- 
ments; the following description is based 
mainly on the type) : Scolex discoid at apex, 
which is depressed in the center, with an oval 
subapical bothrium 0.15 mm long by 0.13 mm 
wide on dorsal and ventral surface. Unseg- 
mented neck uniform in width (about 0.1 mm 
in the type, in which the segmentation com- 
mences 2.65 mm behind the head end). Pro- 
glottides nearly parallel-sided, wider than long 
throughout strobila, with salient posterior 
border, which often may be constricted at pre- 
equatorial level. Inner longitudinal muscle 
bundles comparatively wide apart one from 
another (Fig. 5B). Dorsal and ventral excre- 
tory vessels running in lateral end of medulla, 
lateral to nerve trunk, ventral to terminal 
genital ducts. 
Testes extending longitudinally medial to 
nerve trunk and longitudinal excretory vessels, 
10-15 in number on each side. Vas deferens 
twisted, running outward immediately behind 
vagina. Cirrus pouch pyriform, small, 74-7 7 p X 
5 6-6 5 p in immature proglottides; ejaculatory 
duct narrow, but swollen at base of cirrus 
pouch, opening with vagina on dorsolateral 
margin of proglottis at about pre-equatorial 
level, alternating irregularly from side to side. 
Ovary transversely elongated near posterior 
margin of proglottis on pore side of median 
line, with compact mass of shell gland im- 
mediately behind. Uterine duct winding for- 
ward from behind ovary to uterine sac. Uterine 
sac rounded, almost median near anterior border 
of proglottis, opening midventrally. In fully 
gravid proglottides the uterus distended with 
eggs occupies the whole medulla with uneven 
outline. Eggs oval, operculate, rather thick- 
shelled, 7 7-90 p X 49-6 3 p in life; contained 
ova unsegmented. Vitelline follicles small, 
round, extending profusely in entire cortical 
parenchyma, continuous from proglottis to 
proglottis. Vagina running straight, obliquely 
anterolaterad from behind ovary toward com- 
