324 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, IV.

MacHattie and Chadwick [1932] and many others have admitted that the ova
of the various species of Schistosomes described from man and animals, within
reasonable limits of variation, have a definite and characteristic shape which is
generally regarded as being diagnostic of the species. These authors have also
proved that a very small percentage of females produce ova showing a departure
from the normal shape ; yet the fact remains that a vast majority of them produce
ova each having a characteristic shape which is constant to a given species. Baylis
[1929] and Faust [1930] have given outline drawings of ova of different species of
Schistosomes from mammals and when the outline of the ovum of the parasite in
question is compared with any one of those depicted, it looks different. The ova
of all the females of the species described, resemble each other in their characteristic
shape and the authors therefore believe that that shape is normal to that species.
Chandler [1926] has described Schistosome ova from samples of what he believed
to be human faeces which were collected from defæcation areas, near two villages,
to which pigs had access. These ova resemble in all respects, the ova described in
this paper. Chandler assumed that such faeces, from which he obtained samples,
were passed by human beings because of the nature of the stools and the presence
of ova of Anclyostomes, Ascaris and Trichuris, but, for obvious reasons that can-
not be taken as evidence to prove the correctness of his assumption. The fact that
the Schistosome ova described by him resemble those found in the Schistosomes
collected here from pigs, suggests the probability that the fæces in which he saw
them were from the pigs that had access to the areas mentioned by him, and not
from human beings. The difference in the morphology between this and the other
Schistosomes has been discussed above. Further the various Schistosomes de-
scribed from mammals can be differentiated by the shape of their ova, and since the
shape of the ova of the parasites in question is different from the others, there
appears to be enough justification in making it a new species and it is proposed to
name it "SCHISTOSOMA SUIS." Now that the adult Schistosome and its host
has been found, we suggest to tentatively place S. incognitum Chandler, 1926,
as a synonym of S. suis, because even though the former name is the older it is
only a nomen nudum.

                                          REFERENCES.

Baylis, H. A. (1929). Helminthology Medical and Veterinary. London, B. T. & Cox.
Chandler, Asa, C. (1926). Ind. Jour. of Med. Res., 14, pp. 179-183.
Faust, E. C. (1930). Human Helminthology. London, Henry Kimpton.
Leroux, P. L. (1933). Jl. of Helminthology, 11, No. 1, pp. 57-62.
MacHattie, C. and Chadwick, C. R. (1932) Trans. Roy. Soc. Trop. Med. and Hyg., 26, pp.
147-156.