Gastrocotyline Parasites of Indian Clupeoids — Unnithan 
227 
within the ootype region (Fig. 33). The wide 
median uterus, with cuticularized walls, ascends 
from the distal margin of the ootype, extends 
forward beyond the vaginal region, and opens 
into the unarmed, ventral, uterine pore, imme- 
diately in front of the male pore (atrium mas- 
culinus) (Fig. 32). In one of the specimens a 
collapsed egg, with a body 120 \i long, was ob- 
served at about the middle of the uterus. 
The vitellaria extend from behind the zone 
of the male terminalia to the anterior level of 
the short row of clamps, surrounding the crura 
and their branches but not confluent across the 
median line at the hind end; the vitelline fol- 
licles are spherical, 14-1 6 p in diameter. The 
transverse vitelline ducts are slightly oblique 
and are situated near the posterior end of the 
anterior third of the ovarian zone ; at their con- 
fluence they receive the median vaginal canal. 
The median vitelline duct extends backward 
parallel to the ovary and opens into the vitelline 
ampulla. The genito-intestinal canal is very 
narrow, irregularly wavy, and arises from the 
ootype. It runs obliquely forward to open into 
the right intestinal crus, near the proximal 
limb of the ovary. 
The vaginal pores are unarmed, just supra- 
marginal on each side of the body at about 
0.25-0.52 mm from the anterior end, with the 
right pore usually slightly anterior to the left. 
The two vaginal ducts from the base of the 
lateral vaginal pores unite obliquely as a V 
across the median line to form a long median 
zigzag vaginal duct which runs backward, dorsal 
to the uterus, and opens into the median vitel- 
line duct at the junction of the transverse vitel- 
line ducts, hence indirectly to the ootype region. 
In most of the specimens traces of vitelline mat- 
ter were observed extending forward beyond 
the level of transverse vitelline ducts, into the 
median vaginal duct. Spindle-shaped egg s, with 
a filament at each pole, were seen in worms 
4.5 mm long. 
relationships of Pellonicola elongata gen. 
et sp. nov.: 
1. The elongated ribbon-like body with the 
distinct but short caudal haptor is outstanding 
in Gastrocotylinae. The body proper is free 
from the attachment zone, so the zone of pivot- 
ing in the extreme feeding attitudes is behind 
the testicular zone; but, because of the inequal- 
ity of the attachment basis, the stresses will be 
slightly greater on one side than on the other, 
and so the profile in contracted worms is not 
as symmetrical as in Microcotyle , for instance. 
This slight asymmetry is most obvious in the 
vaginal zone at the neckbase, as it is in the 
most asymmetrical species of Engraulis cobina. 
i. The body axis makes an angle of up to 
60° with the haptor axis. 
ii. The ratio of body width to length is only 
1:10, and of haptor to body length about 
1:57 
2. The unilateral inhibition is far less than 
that in any other genus of the asymmetrical 
gastrocotylines. In this respect it is comparable 
with Scomberocotyle Hargis, 1956, but in that 
genus a metahaptoral wing, or a secondary 
stimulation of the secondary clamp replication, 
accounts for the larger number of clamps on 
one side (Unnithan, 1967^). It is possible that 
further observation on P. elongata may show 
that a similar growth relation exists here and 
that the anterior moiety of the long clamp row 
does represent a metahaptor, the posterior 
moiety being the euhaptor with regular paired 
clamps in the opposite row. If this is so, the 
formative region for the long row would be 
near its middle, and that of the short row at its 
anterior limit, as is usual for the euhaptor. 
i. The long row has a total of 17-22 clamps, 
while the shorter has 8-10. 
ii. All clamps are slightly longer than wide. 
Perhaps this is a generic character. 
iii. The ventral arm of the median spring is 
of a unique vase shape and is split and 
bowed, joining distally in a very shod 
bifurcation. 
iv. The appendix on the short dorsal arm is 
sometimes cruciform, indicating an incip- 
ient cuticularization of the lateral liga- 
ments. 
v. The dorsal arms of the ventral jaw rami 
are remarkably reduced. 
vi. The braces across the middle of the cap- 
sule are stout but lack distally bent artic- 
ular facets. 
3. Two pairs of persistent anchors are pres- 
ent on a telescopic lappet. Anterior anchors are 
