318       Gasterostomatous Parasites of Indian Food-Fishes

The occurrence of Gasterostomatous trematodes in Indian hosts was re-
corded by the author in 1934, 1935 and 1937. In this paper are described
several new parasites found in Indian food-fishes, both fresh-water and
marine.

                    Order—Gasterostomata Odhner, 1905.

                    Family—Bucephalidae Poche, 1907.

                    Genus— BUCEPHALUS Baer, 1827.

                                         BUCEPHALUS INDICUS, N. SP.

Host— Macrones seenghala Day.

Habitat—Intestine.

Locality—Allahabad.

It is a fairly common parasite in the gut of Macrones seenghala found in the
rivers Ganges and Jumna at Allahabad. The infestation, though never heavy,
is nearly fifty per cent during winter months. In the living condition, the
parasite is light brown in colour and does not appear to have any marked
power of contraction and expansion. The body is elongated and somewhat
cylindrical with broadly rounded ends. It is studded with minute backwardly
directed spines which are more closely set in the anterior half of body and
become sparse towards the hinder end. The parasite in permanent mount
measures 1.4—3.2* in length and 0.28- 0.68 in maximum breadth which
occurs across the level of the pharynx. The anterior sucker, measuring 0.16
—0.36 × 0.14- 0.24 in size, has a crown of six well-developed and highly
contractile tentacles of 0.095—0.11 × 0.038-0.046 size. The tentacles
have a broad triangular base and a little further removed, about 0.03 -0.04,
from the anterior tip, possess two fairly well-developed lateral processes,
0.03-0.038 X 0.01 in size, situated on either side.

The pharynx is a circular, muscular structure of 0.08 - 0.14 in diameter
situated in the median line at about the junction of the middle and posterior
third of body length. The mouth lies in a small depression on the ventral body
surface. The pharynx opens posteriorly into a bottle-shaped oesophagus
of 0.06-0.18 in length. The intestine is a simple ovoid sac measuring
0.24-0.4 X 0.12-0.2 in size and extending forwards from the pharynx
to the anterior level of the ovary.

The two testes are of slightly varying size and shape. They are situated
one behind the other on the left side of the body usually in the first two
thirds of the posterior third of body length. The anterior testis, measuring-
0.14—0.32 × 0.12- 0.32 in size, is separated from the posterior testis of 0.12
— 0.38 X 0.12 — 0.28 in size by the initial part of the uterus and the vitalline

                                    * All measurements are in mm.