FURTHER STUDIES ON THE ENDAMBÆ PARASITIZING OPALINID CILIATES

¹ From the Osborn Zoölogical Laboratory, Yale University, and the Zoölogical Laboratory, University of Pennsylvania

1. The ambæ parasitic in the opalinid ciliates have a very wide geographical distribution, being found in Egypt, China, Ceylon, the United States, Panama, Brazil, Uruguay and Chile.

2. Different species belonging to all the four genera of the family Opalinidæ—Protoopalina, Zelleriella, Cepedea, and Opalina—have been found parasitized by the ambæ.

3. There is a great range of variation in the percentage infection of opalinids in different individual anuran hosts. In some hosts it may be as low as 2 per cent, whereas in some others 100 per cent of the opalinids may be infected.

4. The ambæ have been found within numerous opalinid cysts. Each cyst may contain one to seven ambæ although the majority of cysts harbor only two, three, or four of them. The presence of ambæ in the encysted opalinids probably constitutes an important method of transmission of ambæ from adult anurans to tadpoles.