H. D. SRIVASTAVA                                   215

The genus contains a large number of species— Prosthogonimus ovatus
[Rudolphi, 1803] P. cuneatus [Rudolphi, 1809], P. pellucidus [von Linstow,
1873]. P. japonicus [Braun, 1901]. P. anatinus [Markow, 1902], P. putsch-
kowskii [Skrjabin, 1913], P. dogiele [Skrjabin, 1914], P. vitellatus [Nicoll, 1915],
P. rudolphi [Skrjabin, 1919], P. brauni [Skrjabin, 1919], P. skrjabini [Zakharow,
1920], P. longus-morbificans [Seifried, 1923], P. furcifer [Railliet, 1924], P.
fuelleborni [Skrjabin and Massino, 1925], P. horiuchii [Morishita and Tsuchi-
mochi 1925], P. k arausiaki [Laymann, 1926], P. orientalis [Yamaguti, 1933],
P. querquedudae [Yamaguti, 1933], P. macrorchis [Macy, 1934], P. leei [Hsu,
1935]. In the proceedings of the Indian Science Congress, 1929, Gideon
published an abstract of a paper on a new species of the genus Prymnoprion
which he had obtained from the rectum of Ibis melanocephala. The genus
Prymnoprion has now been proved to be synonymous with Prosthogonimus.
The full paper has not yet been published and in the abstract the author has
given no description whatsoever of the parasite, which is, therefore, con-
sidered as ' species inquizendae '.

On account of the character of its vitellaria which are arranged in defi-
nite groups and the absence of heavy uterine coils from the pre-acetabular
region the new species, P. indicus, is referable to the sub-genus Macroge-
notrema [Skrjabin and Baskakow, 1925]. By its above mentioned characters
it can be easily distinguished from P. ovatus and P. dogiele. From P. macror-
chis the Indian species can be distinguished by the length of the oesophagus
and intestinal caeca, size ratio of suckers, position of testes and vitellaria
and by the absence of the spine in the egg. In having the acetabulum more
than twice the size of the oral sucker the new species can be separated from
P. furcifer, P. japonicus and P. pellucidus in which the suckers are approxi-
mately of equal size. P. indicus differs from P. vitellatus in the size ratio
of suckers and in the extent of vitellaria and the position of testes which
are confined to the anterior half of body in the latter species. In the pos-
terior extent of its cirrus sac which does not reach the ventral sucker and ends
far in front of it, the Indian species differs from P. brauni and P. putschkowskii.
In the post-ovarian position of testes and the pre-acetabular extent of vitel-
laria, the new species differs from P. skrjabini and P. k arausiaki in which the
testes lie more or less in level with the ovary and the vitellaria do not reach
the anterior border of the acetabulum. The definitely post-acetabular charac-
ter of the vitellaria in P. anatinus, P. horiuchii and P. orientalis distinguishes
them from the Indian representative in which the vitellaria extend to a little
distance in front of the acetabulum. In P. cuneatus the acetabulum is just
twice the size of the oral sucker and the vitellaria, which do not extend in
front of the acetabulum, are not divided into bunches, while in P. indicus
the acetabulum is more than twice the size of the oral sucker and the vitellaria,
which extend in front of the acetabulum, are divided into distinct bunches
about seven to nine in number. P. rudolphi can be distinguished from the Indian
form by the size of its acetabulum which is approximately twice the size of
the oral sucker, the intercaecal character of its uterus and the anterior extent