PARASITIC PROTOZOA FROM CEYLON. 75 
occurring in R. tigrina, R. cyanophlyctis, R. limnocharis, and, R. 
hexadactyla, but he does not state from what parts of Asia the frogs 
came. He gives 110 y xX 60 wu as the average dimensions. The 
average size of my forms, however, is about 80 wu x 50y. Apart 
from this, Bezzenberger’s description of B. helene applics equally 
well to B. ovale. The peristome has the same form, the meganucleus 
is kidney-shaped, lying posteriorly, with the micronucleus in the 
hollow. I have omitted to figure the organism, as Bezzenberger’s 
figure of B. helene is almost identical. 
I found numerous animals undergoing division, and also found 
encysting and encysted forms. These present no essential differ- 
ences from what has already been described in other members of 
the genus. The cysts are ovoid, and measure ca. 54 x 44 u. 
In addition to the large forms just described, I found numerous 
smaller forms—also dividing actively—which were identical in every 
way except in size. They were only about two-thirds the size of 
the larger animals. Whether these represcnt another species or not, 
I am unable to decide. 
(3) Balantidium hyalinem, n. sp. 
I propose this name for the organism which occurs in the duode- 
num of &. tagrina. It does not differ markedly from other duodenal 
forms, namely, B. duodeni, Stein (in Rana esculenta and R. tempo- 
raria), and B. rolundum, Bezzenberger (in R. esculenta, var. chinensis). 
It is often present in large numbers in the small intestine, and when 
alive its protoplasm is more hyaline than that of any other Balan- 
tidium which I have seen. 
The organism (fig. 19) is oval, with a straight mouth extending 
almost to the middle of the body. The meganucleus is posteriorly 
placed, and is ovoid. The micronucleus can nearly always be scen 
at one end of the meganucleus, not in the middle (cf. fig. 19). 
There is one contractile vacuole. In the anterior region the curious 
striated or granular triangular area, which is characteristic of 
B. duodent and B. rotundum, is usually clearly scen (sce fig. 19). 
As in these forms also, the cilia are long and well developed over 
the whole body. The average dimensions are ca. 74 4 X 56 wu. 
(A curiously long and slender form has been described by Bezzen- 
berger—under the name B. gracilis—from the small intestine of 
Rana hexadactyla and R. cyanophlyctis.) 
NYCTOTHERUS. 
In addition to Nyctotherus macropharyngeus, Bezzenberger,* 
which I found in R. tegrina in Colombo, I found a species of 
Nyctotherus in Bufo melanosticius and Rhacophorus maculatus at 
Peradeniya. It appears to be the same species in both hosts, and 
I propose to name it— 


* This is a very large species. Its most striking feature is its very long and 
spirally wound pharynx. 
