Gastrocotyline Parasites of Indian Clupeoids — Unnithan 
219 
bearing the main row of clamps has more ex- 
tensive outer branches, particularly in the hap- 
toral wing, which are accompanied by vitel- 
laria. This winglike expansion of the haptor is 
similar to that in Engraulicola micropharyngella 
described above, but although the present worms 
are on the whole smaller, the haptor is stouter. 
All the clamps have relatively long muscular 
stalks (about as long as the width of the 
clamps) which project sideways in close file. 
As in the previous species, the clamps increase 
in size toward the middle of the row, where 
there is a slight irregularity. This may indicate 
the end of the euhaptor and the beginning of 
the metahaptor, which tends to grow with in- 
creasing independence of the body proper, its 
anterior part being free from it— as the meta- 
haptoral wing (Fig. 12). The long row makes 
an angle of only about 30° with the body axis. 
There are always two remnant clamps on the 
inhibited side, smaller (20 >< 28 p-28 X 
36 p) and resembling their opposite primaries. 
The long row is more than half the length of 
the worm, with 40-48 clamps, each 28 X 40 p— 
28 X 60 p. 
The terminal lappet is trapezoidal, 0.04 X 
0.02 mm, with two pairs of anchors. The an- 
terior anchors are 28 p long and slender; the 
hook is less strongly curved (only one-eighth 
to a quarter of a circle), with a short stepped 
spur, projecting at right angles at the end of 
the slender handle which is more than half the 
total length (Figs. 14 and 15). Thus there is 
a strong resemblance to the anterior anchors of 
Engraulicola micropharyngella. The posterior 
anchors generally resemble those of the last 
species, but the simple hook is barely one-third 
as long and is less curved (about half a circle), 
while in the last species the hook was more 
than half a circle (cf. Figs. 14 and 10). 
The clamp structure is quite distinctive in 
detail (Fig. 13) ; the larger clamps are as much 
as twice as wide as they are long. In sharp con- 
trast to the two previous species, the ventral 
arm of the median spring is broad and widely 
bifurcated in a thick pointed fork. The dorsal 
arm carries a V-shaped stout appendix with 
: arms widely diverging. The braces are not bent 
i at the posterior ends to form articulating facets, 
as in the preceding species. 
The testicular zone is entirely flanked by the 
haptor flange, which extends over the hind end 
of the ovary also, so that the pivoting axis is 
in a thicker part of the worm and the torque 
here would account for the broad haptoral wing. 
The testicular zone is not involved in the torque 
and the 2-4 files are rather regular and compact 
(Fig. 12). There are 15-31 testes, ovoid or 
spheroidal, with one or two parovarian testes. 
The vas deferens is long and wide, arising from 
the median anterior testicular zone and extend- 
ing forward as a zigzag duct to open into the 
base of the penis. The anterior extremity of the 
vas deferens, before it joins the penis, is straight, 
forming the ejaculatory duct; this has a poste- 
rior dilatation between the horns of the vaginae 
functioning as the seminal vesicle (Fig. 17); 
the penis is muscular, ventral, situated about 
0.18-0.2 mm from the anterior end, and bear- 
ing a corona of 10 sharp hooks, but its tip lacks 
forceps spines. The atrium masculinus is un- 
armed and circular, with a muscular rim and a 
thick ring of radial muscle fibres but no project- 
ing membranous collar (Figs. 16a and 16b). 
The ovary takes the form of an inverted U 
with a long narrow proximal (outer) limb and 
a wide short distal (inner) limb, situated in the 
middle third of the body, in front of the tes- 
ticular zone. The thin and narrow oviduct de- 
scends from the distal end of the ovary and 
opens into the fertilization chamber, through 
the well-developed, spindle-shaped ovijector 
(Fig. 17). The ootype is surrounded by closely 
packed Mehlis gland cells. The uterus ascends 
from the ootype to open into the unarmed 
uterine pore in front of the atrium masculinus. 
Eggs were seen in only one of the specimens. 
The vitellaria extend from the intestinal bi- 
furcation to almost the distal ends of the crura ; 
they are not confluent across the median line, 
and their spherical follicles are 8-10 p in di- 
ameter. The transverse vitelline ducts meet to 
form the median duct at the anterior quarter of 
the ovarian zone, as in E. triaptella , but here 
they are joined by the lateral vaginal ducts. The 
median vitelline duct is broad anteriorly and 
tapers posteriorly to open into the vitelline am- 
pulla, which is feebly demarcated in most of 
the specimens. The genito-intestinal canal is well 
differentiated, arising from the ootype close to 
the ovijector, and running obliquely into the 
right crus. 
