H. D. SRIVASTAVA                                 369

account of the presence of oral diverticula. Within the family the genus falls
under the subfamily Cladorchinae Fischoeder, 1901, and in its affinity stands
nearest to Cladorchis Fischoeder, 1901. It resembles the latter genus in the
presence of a genital sucker but differs in the conical shape of its body, size,
position and character of the acetabulum, size of the genital sucker and the
position of the gonads.

                             GENERIC DIAGNOSIS

Fairly large sized amphistomes with smooth, conical body. Oral sucker
with paired pouches; acetabulum very large, circular, posteriorly directed,
papillose and forming the base of the conical body. Oesophagus and oeso-
phageal bulb present; caeca extend to hinder end. Testes, two-lobed, extra-
caecal and slightly symmetrical, placed one on either side about the middle of
the body. Cirrus sac enclosing vesicula seminalis, pars prostatica surrounded
by prostate gland cells, and ductus ejaculatorius present. Genital pore
slightly sinistral and in level with the oesophageal bulb. Genital sucker very
large but feebly muscular. Ovary compact, situated near the blind end of the
left caecum. Laurer's canal present. Vitellaria follicular, arranged in the
form of an U, beginning from the hinder end of the testes and meeting pos-
teriorly in the intercaecal space. Uterus pre-ovarian, intercaecal; eggs
numerous, operculate and large sized. Excretory system H-shaped; lym-
phatic system consists of three longitudinal canals. Parasites of fresh-water
fishes.

        TYPE-SPECIES.—NICOLLUDISCUS GANGETICUS

        ORIENTODISCUS LOBATUM, GEN. ET. SP., NOV.

Four specimens of this species were collected from the rectum of one out
of a number of specimens of the host examined in 1934. The smooth elongated,
fusiform body measures 5.0 to 7.0 in length and 1.12 to 1.82 in maximum
breadth across the level of the testes. The anteriorly directed oral sucker is
ovoid in outline and opens to the outside through a small vestibule. It measures
0.22—0.24 × 0.26—0.3 in size and has two postero-lateral pouches of 0.1—
0.12 in diameter. The acetabulum is a strongly muscular, cup-shaped structure
of 0.68—0.76 in diameter and is situated sub-terminally at the posterior end
of the body. The narrow oesophagus, 0.44—0.54 long, is continued poster-
iorly into a spindle-shaped oesophageal bulb, 0.3—0.5×0.14—0.22
in size. The intestinal caeca are long, narrow tubes with crenated outer
margins. They extend in a somewhat wavy course up to the posterior level
of the ovary. Both the oesophagus and its bulb are surrounded by a large
number of deeply staining cells,