216 
trocotyle and Engraulkola : the hook is barely 
a quarter of a circle, with the handle consider- 
ably longer, while the stout spur is at right 
angles to the handle. The posterior anchors 
(Fig. 10) are also unusual in having an in- 
cipient spur behind the short hook; the total 
length of these anchors is 16 p. 
The clamp structure shows slight variations 
from that of Engraulkola : there is a marked 
gradation of size toward the middle of the long 
row. The clamps are much wider than long, 
except for the first and next anterior clamps, 
which, like the two remnant primaries of the in- 
hibited side, are more nearly squarish (Fig. 8). 
The 20-39 testes are oval, 28 X 40 p-36 X 
48 p, arranged in 4-5 files in the intercrural 
field behind the ovary but with a few parovarian 
testes on the left side. The narrow vas deferens 
arises from the postovarian testes, extends for- 
ward on the left side of the body, parallel to 
the vitelline duct and enlarges into a seminal 
vesicle near the anterior end of the median 
vitelline duct. From the anterior margin of the 
seminal vesicle, the vas deferens continues for- 
ward and opens into the base of the penis, some 
distance anterior to the intestinal bifurcation. 
The penis is muscular and armed with a corona 
of 12 recurved hooks around its bulb-like base, 
and there is a forceps-like double spine within 
(Fig. 11). The forceps spines appear rather 
shorter than in Engraulkola. Male genital pore 
is strengthened by a rim of radial muscle fibres 
but is without a projecting collar, and is situ- 
ated at about 0.27 mm from the anterior end 
of the body. 
The inverted U -shaped ovary occupies a field 
in the middle of the body’s length and it is 
about one-tenth as long as the latter, the ova 
as usual becoming bigger toward the oviduct. 
The oviduct arises from the distal end of the 
ovary and enlarges into a small sphincter-like 
ovijector which continues through the ootype 
region and opens into the fertilization chamber 
near the vitelline ampulla. The uterus can be 
traced forward from the anterior margin of the 
ootype, parallel to the vas deferens, and it 
opens into the unarmed uterine pore situated 
immediately in front of the male pore. 
The paired vaginal pores are unarmed and 
submarginal and lie in front of the ovarian 
zone at two-thirds the distance from the male 
PACIFIC SCIENCE, Vol. XXI, April 1967 
terminalia to the anterior end of the ovary. The 
vaginal ducts are S-shaped and in the specimens 
examined were distended with sperm; they run 
backward and unite in the zone of transverse 
vitelline ducts to enter the wide median vitelline 
duct which extends backward, narrows poste- 
riorly, and opens into the ootype, in the small 
vitelline ampulla. Thus, there is no true median 
vaginal duct. 
The vitellaria extend from the region of in- 
testinal bifurcation to the distal ends of the 
crura and are not confluent across the median 
line even in the region of the crural bridges; 
the spherical follicles are 8-12 p in diameter. 
The transverse vitelline ducts meet along with 
the lateral vaginal ducts immediately anterior 
to the ovarian zone, to form the median vitel- 
line duct which also functions as a vaginal duct. 
The genito-intestinal canal connects the base of 
the ootype with the right intestinal crus, passing 
sharply obliquely forward across the proximal 
region of the ovary; its union with the right 
crus is in the midovarian zone (i.e., more an- 
terior than is usual). 
relationships OF Engraulixenus malabari- 
CUS GEN. ET SP. NOV.: 
1. Engraulixenus has an elongated tapering 
body, slender anteriorly, with a long foot- 
shaped hindbody tapering backward and which 
has an unusually prominent heel with a spurlike 
extension; this region is the typical haptoral 
wing (perhaps a metahaptor: see Unnithan, 
1967^), which receives short wide branches 
from the adjacent intestinal crus which branches 
more or less profusely in the anterior part of 
the wing; these gut branches carry with them 
vitelline follicles. The haptor extends slightly 
obliquely at only 25° to the body axis for at 
least 50% of its length; thus the zone of pivot- 
ing of the attached worm is between the wide 
testis zone and the ovarian zone. The torque 
strains set up have not greatly disturbed the 
symmetry of the body proper but doubtless 
account for the haptoral wing and subjacent 
lateral field. The arc of feeding exploration is 
evidently extensive because of the slender con- 
tractile forebody. Thus, Engraulixenus is less 
symmetrical than Gastrocotyle. 
2. The inhibited clamp row retains two of 
its primary clamps in all individuals. 
