371 
ON A NEW CILIATE, BALANTIDIUM O VATUM, SP. NOV., 
AN INTESTINAL PARASITE IN THE COMMON 
COCKROACH (BLATTA AMERICANA). 
By EKENDRANATH GHOSH, M.Sc., M.D., 
Professor of Biology, Medical College, Calcutta. 
(With 1 Text-figure.) 
The parasite herein described was found in the intestinal contents of Blatta 
americana at Calcutta. A single specimen was observed. 
Diagnosis: Body elongately ovate, wider posteriorly than anteriorly, 
slightly less than twice as long as its greatest diameter and broadly oval in 
transverse section. Anterior end rounded and slightly bent to the side of the 
peristome. Posterior end abruptly tapering to a point. Side with the peristome 
slightly depressed in front and convex behind. Side opposite to the peristome 
convex. Peristome small, tubuliform, about one-fifth the body-length, 
directed backwards and medianwise and slightly twisted from right to left. 
The peristome has an undulating membrane running along its postero-lateral 
portion and a row of stout cilia in its anterior portion, this row being con¬ 
tinuous with the long anterior body cilia. Body surface smooth. Body cilia 
long; a row of long and somewhat stout cilia at the anterior end. Ectoplasm 
generally thin, but thick near the anterior and posterior ends of the body. 
Endoplasm densely filled with coarse granules and presenting a comparatively 
light area opposite to the peristome. Macronucleus broadly oval, situate in 
the middle of the body. A large contractile vacuole is seen posteriorly, with 
an oblique anal canal opening in front of the posterior end. Length 0*085 mm. 
This parasite forms the second example of Balantidium found in the in¬ 
testine of the cockroach. It differs from all the known species in the presence 
of an anal canal in connection with the contractile vacuole. It is distinguished 
from B. blattarum (Parasitology , xiv. 15-16) in its shape, the position of the 
undulating membrane, and in the thinness of the ectoplasm. 
