Gastrocoty line - Parasites of Indian Clupeoids — XJnnithan 
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long, narrow, unbranched, and bifurcating into 
the intestinal crura at the level of the male 
genital pore; crura with long irregular outer 
and short simple inner branches; both crura 
extend into the haptor and terminate at dif- 
ferent levels, one extending farther than the 
other. In the haptoral region the crura are un- 
branched and the ends are not confluent. 
In the specimen examined the haptor bears 
a long row of 27 clamps on one side, and a 
single clamp on the other. It is inclined to the 
body axis at 45°-60°, and is about 35% of 
the body length. All the clamps are of the 
same structure, though they vary in size from 
16 X 20 |i to 28 X pi. The anteriormost 
clamp of the long (left) row is the smallest 
and the single clamp on the right side is more 
or less of the same size. It is reasonable to 
expect amphitypy, the long uninhibited row 
being on the left or right according to the 
location of the worm on the gill; further col- 
lection may show this relationship. 
Clamps typically gastrocotyloid in structure: 
dorsal arm of median spring short and narrow 
with a thin V-shaped cuticular projection from 
its distal end; ventral arm of median spring 
long and narrow, distally bifurcated; base of 
clamp with a thin, narrow, heavily cuticularized 
hinge ligament on each side, connecting the 
median spring with the base or region of 
articulation of the jaw sclerites; dorsal and 
ventral jaw sclerites of the two sides sym- 
metrical; dorsal arm of ventral jaw reaches to 
the level of the bifurcation of the dorsal arm 
of the median spring ; oblique sclerites 
("braces”) long and narrow, with their distal 
ends touching in the median line, where their 
backwardly bent tips form an articulating sur- 
face, just within the dorsal jaw (Fig. 2). 
Terminal lappet small and cylindrical, 21 pi 
broad and 36 p long, demarcated from the rest 
of the haptor by a small constriction and armed 
with two pairs of symmetrically placed anchors : 
anterior pair typically sickle-shaped, 24 \i long, 
the hook being about three-eighths of a circle. 
The spur root is short and bent posteriorly to- 
ward the point of the sickle, while the handle 
is less than half the total length (75% of the 
sickle) (Fig. 3a). It is interesting to note 
that the spur pointing posteriorly toward the 
point is also characteristic of the large anchor 
of Gastrocotyle (Llewellyn, 1957: Figs. 12 and 
22). The posterior pair is exceptionally small, 
with sharply reflexed hooked ends; their over- 
all length is 8 pi (Fig. 3b). 
The testes are all postovarian; there are about 
27 small spheroidal follicles in 2-3 irregular 
files extending more or less to the hind end of 
the shorter intestinal crus or halfway down the 
haptor. The vas deferens runs forward, curving 
to the right around the ovarian zone beyond 
which it becomes median and opens into the 
base of the penis, apparently without a vesicular 
dilatation. The atrium masculinus is in the zone 
of the intestinal bifurcation. The cuplike penis 
has a thick muscular wall, its rim armed with 
a corona of 8-10 hooked spines with their 
tips converging. From the centre of the penis 
cup on the penis head is a forceps-like, lightly 
cuticularized structure 13-16 pi long, much 
longer than the penis hooks, and projecting 
slightly beyond the penis corona (Figs. 4 and 5) . 
No collar was seen like that described by 
George (1961) for the genotype. 
The ovary is an inverted U, its field 210 X 
63 ji, situated in front of the testes; its outer 
longer limb is narrow and the distal inner limb 
is thicker and contains larger ova. The oviduct 
arises from the distal end of the ovary, runs 
backward, and opens into the ootype through 
a short narrow basal loop (Fig. 6) ; the uterus 
arises from the ootype close to the oviduct, 
runs forward along the median line, and opens 
near the male genital opening. Eggs spindle- 
shaped, 40 X 24 pi. 
Vitellaria massive, extending from the level 
of intestinal bifurcation to the tips of each 
intestinal crus and covering the crural branches, 
not confluent across the median line; vitelline 
follicles spherical, 8-10 pi in diameter. The 
transverse vitelline duct lies at the level of the 
first third of the ovarian zone, and the median 
vitelline duct tapers slowly until it reaches the 
ootype. 
The ootype is surrounded by few scattered 
Mehlis gland cells. The genito-intestinal canal 
curves toward the right side and opens into 
the right crus in the midoviduct zone. 
The median dorsal vagina is unarmed and is 
situated in the angle of the intestinal bifurca- 
tion, immediately behind the muscular un- 
armed rim of the atrium masculinus and sur- 
