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PACIFIC SCIENCE, Vol. XXI, April 1967 
slender and tapers to a minutely notched 
tip. 
iv. The dorsal appendix on the spring is a 
simple V shape. 
v. The braces are slender and nearly straight 
and lack the bent articular distal facet in 
E. triaptella. There is no description or 
figure of the secondary clamps for E. 
thrissocles. 
3. The two pairs of persistent anchors on 
the lappet are of characteristic shape in both 
species. The genotype retains a pair of minute 
larval hooks at the tip of the lappet. 
i. The anterior anchors are slender, with 
feebly curved hooks (about one-third to 
one-half a circle), and with a knoblike 
spur and the handle barely half or less 
of the total length (40 p). 
ii. The posterior anchors are C -shaped or 
sharply reflexed simple hooks with negli- 
gible handles (root). 
4. The penis head is absolutely devoid of 
forceps, the corona hooks are straight. 
i. There are 10 penis hooks in E. triaptella 
but 12 in E. thrissocles. 
ii. There are 9 to 12 irregularly shaped, 
rather large testes in two files, with some 
of the files (nearer the clamps) paro- 
varial. In E. thrissocles there are perhaps 
no parovarial testes. 
iii. There is no intercalary vesicula seminalis 
on the vas deferens. 
5. The single median dorsal vagina leads to 
a median duct independent of the vitelline 
ducts. 
i. The zone of the vulva is midway between 
the male genital pore and the ovary. 
ii. The vitelline ducts are horizontally trans- 
verse at the first quarter of the ovarian 
zone. 
6. The moderately ovoid pharynx is only 
about twice as long as the oral pouches. 
i. The oral pouches’ mean diameter is about 
70% of that of the pharynx (about 56% 
in the genotype). 
ii. The lateral crural branches are extensive 
in the haptoral wing, but there are no 
intercrural bridges and the crura extend 
without dilation to near the posterior tip 
of the body in both species. 
The two species are closely related yet clearly 
distinct and occur on different species of Thris- 
socles , the genotype occurring in the northern 
Bay of Bengal (Puri) and E. triaptella in the 
South Arabian Sea and at two stations in south- 
ern Kerala. 
Pellonicola elongata gen. et sp. nov. 
Figs. 26-33 
Several specimens of this new gastrocotyline 
were obtained from the gills of Pellona (llisha) 
hrachysoma (Blkr.) examined at Trivandrum in 
1955. A single fish 17 cm long was examined 
on July 5, and 4 parasites were found on its 
outer gills; a single female fish 17 cm long, 
examined on August 27, had 4 parasites. From 
5 fishes 18 cm in average length, examined on 
July 27, 14 specimens were obtained. The 4 
specimens collected on July 5 proved to be the 
longest among the total of 22 specimens. 
The long, narrow, ribbon-like body (2.25- 
4.5 mm long, maximum width 0.25-0.48 mm, 
or one-tenth its total length), tapers gently for- 
ward to a nearly straight neck little more than 
one-tenth of the total length and itself one-fifth 
to one-quarter as long as wide. The middle 
third of the body is expanded 25% to accom- 
modate the ovarian zone and reaches its maxi- 
mum at the proximal ovarian zone; behind this 
the testicular zone is almost straight-edged and 
is as wide as the preovarian zone (Fig. 26). 
The haptor is relatively far shorter than in any 
other gastrocotyline yet known, barely one-fifth 
the total length (0.525 X 0-15 mm-1.0 X 0-3 
mm), one clamp row being twice as long as the 
other, with subsequal clamps ending in a short 
telescopic lappet. 
The subterminal funnel-shaped mouth is sur- 
rounded by a highly muscular spherical-to-oval 
organ having a deep circular lip with a ventral 
notch, and a chamber measuring 45-50 p. Be- 
hind it are the ovoid oral pouches, 20 X 28 p- 
24 X 36 p, and these have thick walls and long 
muscle fibres extending down the length of the 
neck (Fig. 27). The pharynx is a large ovoid 
structure, 34 X 38 p-36 X 40 p. The mean 
diagonal of the oral pouches is about 61-78% 
