H. D. SRIVASTAVA                                 371

The testes, two in number, are lobed, massive structures situated one
behind the other in the intercaecal space. The anterior testis, measuring
0.7—1.04 × 1.14 in size, lies at the end of the anterior half of body length.
The posterior testis, 0.64—1.12× 1.66, is situated behind the anterior testis.
The vesicula seminalis is a fairly thick transversely coiled tube divisible into
vesicula seminalis interna and externa. The small egg-shaped cirrcus sac,
0.22—0.3×0.12—0.2 in size, encloses a small portion of the vesicula semi-
nalis, a small tubular pars prostatica surrounded by prostate gland cells and a
minute ductus ejaculatorius. The genital pore lies immediately behind the
intestinal bifurcation.

The ovary is slightly triangular in shape with a deep notch in its base
which is directed towards the blind extremity of the right caecum. It is of
0.24—0.3×0.22—0.38 in size, and is situated in the intercaecal space slightly
to the right of the median line at one-fourth to one-seventh of body length
from the hinder end. A small Laurer's canal is given off from the oviduct.
The spherical shell gland mass, 0.22—0.3 in diameter, lies a little obliquely
behind the ovary. The vitellaria consist of a number of irregular follicles
extending laterally to the caeca from the level of the anterior margin of the
acetabulum to that of the middle of the oesophageal bulb. At the posterior
end they extend a little towards the median line. The uterus consists of a
transversely coiled ascending tube containing a number of eggs 0.114—0.129
×0.064—0.076 in size. The excretory system consists of a pair of lateral
tubes which form characteristic loops round the caeca and posteriorly open
into the excretory bladder situated dorsally to the acetabulum. The lymphatic
system consists of three pairs of longitudinal tubes.

In its affinity the genus Orientodiscus stands nearest to Chiorchis (as
revised by Southwell and Kirshner, 1937). The characteristic feature of the
new genus is its excretory system. The anterior extent of the vitellaria also
is rather unusual.

                        GENERIC DIAGNOSIS

Body smooth, fusiform ; oral sucker with paired pouches; oesophagus,
oesophageal bulb and pouches present; caeca extend posteriorly to the level of
the ovary ; acetabulum strongly muscular, cup-shaped and subterminal.
Testes two, massive, intercaecal and tandem ; anterior testis situated at the
base of the first half of body length. Cirrus sac present; vesicula seminalis
divisible into interna and externa. Ovary situated at posterior fourth to
seventh part of body length. Laurer's canal present. Vitellaria follicular,
lateral, extracaecal, extending from the level of the oesophageal bulb to the
anterior margin of the acetabulum. Uterus intercaecal, pre-ovarian ; eggs
many and operculate. Excretory system consists of two lateral tubes which
form typical loops round the caeca ; excretory bladder dorsal to the acetabu-
lum. Lymphatic system consists of three pairs of longitudinal canals. Para-
sites of fresh-water fishes.