150 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ IV, II.
the degree of contractibility possessed by the animal these differences are of a slight
character as to be negligible." " The differentiation of the cephalic gland cells into
coarsely-granular and finely-granular cells is a physiological rather than a morpholo-
gical difference." Sewell further remarks that " the final test of the identity of this
form with that of Schistosoma japonicum lies in the similarity or otherwise of the
adults". The present form from the pig was found on careful examination to
resemble in almost all the respects S. japonicum particularly in respect of the
alimentary canal and the number of testes which in all cases were typically seven.
The only points of difference were the smaller size of the worms and the tuberculate
nature of their cuticle. To the question of the difference of dimensions much
importance cannot be attached, dependent as it is on several factors such as the
contraction, age of the worms, etc. In regard to the tuberculate nature of the
cuticle my recent studies on this group of worm [Bhalerao, 1932], have shown that
this feature has not much significance, variable as it is within the limits of the same
species. Although some workers such as Montgomery [1906], Price [1929] and
Brumpt [1931] have regarded this feature as of importance in differentiating one
species of schistosome from the other, my previous studies on S. spindalis and
Ornithobilharzia turkestanicum have indicated conclusively that this feature is not
constant even within the range of the same species. The present example only
forms an additional support to the conclusion that I had previously reached in this
connection. In conclusion it may be remarked that both these differences merge
into insignificance in so far as the specific identity of the parasite is concerned and
for this reason it is considered that the specimens from the pig in Calcutta are S.
japonicum. Considered from the view point of geographical distribution it is quite
appropriate to expect the occurrence of this fluke in India as it occurs in the adjoin-
ing countries in the eastern zone of the Asiatic continent, viz., China, Japan,
Formosa and Phillipines and Africa in the west.
In the end one can not fail to appreciate the fact that both the cercaria and the
adult have been recorded from the same locality, viz., Calcutta. One can, moreover,
correlate the smaller size of the body of the cercaria with the smaller size of the
adult worms compared with the larger size of the cercaria and adult of a typical
S. japonicum. It is more than the scope of the present communication to correlate
the tuberculate nature of the cuticle with any structure in the larval organization.
One fact, however, seems to be apparent that although specifically the struc-
ture and the organisation of the adult and cercaria of Schistosoma japonicum are the
same as those of the adult schistosome of pigs in India and their supposed cercaria
from Indoplanorbis exustus and Limnœa amygdalum, the differences of the size and
the nature of the cuticle are sufficient to distinguish one variety of the species from
the other, but the writer is not in favour of creating several varieties within the