H. D. SRIVASTAVA                          321

vitellaria and the shape of excretory bladder, B. indicus resembles slightly B.
tridentacularia, but it differs from the latter in the number of tentacles, anterior
extent of cirrus sac and vitellaria, shape of anterior sucker and the difference
in the size of the various organs.

                          BUCEPHALUS GANGETICUS,N. SP.

Host— Macrones seenghala Day.

Habitat—Intestine.

Locality—Allahabad.

Only two specimens, one immature, of this parasite were collected from
the gut of one out of about four dozens of specimens of the host examined.
In the living condition the parasite is of light brown colour and exhibits con-
siderable power of contraction and expansion. The elongated and nearly
uniformly broad body is covered with minute, backwardly directed spine.; and
measures 1.76 in length and 0.38 in breadth. The anterior sucker has a
diameter of 0.2 and is placed a little subterminally on the ventral body surface.
It has a dorsal crown of four cylindrical and highly contractile tentacles of
0.08 X 0.02 in size. The tentacles are studded with minute, pointed spines.

The small, circular pharynx of 0.06 in diameter is situated in the median
line at the middle of the body length. It leads posteriorly through a very
short and narrow oesophagus into a saccular intestine of 0.2×0.14 in size.

The gonads are situated behind one another to the right of the median line
in the posterior half of the body. The hinder testis is situated at one sixth
of the body length from the posterior end and measures 0.18 × 0.14 in size.
It is separated from the anterior testis, which measures 0.22 × 0.18 in size,
by the initial part of the uterus. The cirrus sac is an elongated, tubular
structure measuring 0.74 × 0.14 in size and reaching anteriorly up to the
hinder end of the intestine. It encloses a well-developed, ovoid vesicula
seminalis, 0.16 × 0.1, a long, tubular, 0.4 × 0.1, pars prostatica surrounded
by prostate gland cells and a short and narrow ductus ejaculatorius of 0.1 in
length. The ductus ejaculatorius opens into the genital sinus at the base of the
genital tongue or cone. The genital sinus is surrounded by gland cells which
secrete the wall of the spermatophore. It opens to the outside at the hinder
end very close to the excretory pore.

The ovary is pear-shaped and measures 0.16 X 0.1 in size. It is situated
in the space between the anterior third of the anterior testis, posterior half of
the intestine and the right body wall. The shell gland complex lies between
the two testes and the right body wall. Laurer's canal is present. The
vitellaria are composed of small, rounded follicles arranged longitudinally,
on the lateral sides of body, beginning from a little in front of the pharynx to
the anterior fifth of body length. The uterus is well developed and contains a
large number of oval eggs of 0.015—0.023 X 0.0076—0.0095 in size. A
small, tubular metraterm is present.