Protozoa Parasitic in Frogs, Part II. 345 



the figure shows the characteristic corkscrew-like folds that the 

 animal presents when moving along. It also shows the slight 

 turn of the " head " end that is noticed during locomotion. 



The species at first sight resembles 0. intestinalis slightly in 

 outline and position of the nuclei, but it differs from it in that 

 the anterior end is broader in proportion to the posterior, 

 which tapers more and ends more sharply than in 0. intestinalis, 

 and in that the body is slightly flattened and so would not be 

 circular in cross section. 



Opalina acuta, n. sp. 



This other new species from Limnodynastes dorsalis is much 

 smaller than O. dorsalis, and tapers very much towards the 

 posterior end, forming a long tail-like process (Plate LXX., Fig. 4)^ 

 The average length is 257 /x, and tlie breadth at its widest 

 portion of about 38/^. The anterior nucleus is situated about 

 57/x from the front end, and the posterior about 10/x further 

 on, and generally slightly nearer the ventral surface. The cilia 

 are well developed on the body portion, but gradually diminish 

 in size and number on the posterior process, until for a length 

 varying from 25 /x to 50/x from tlie tip of the process there 

 appear to be none. • As the animal moves along, the anterior end 

 is slightly raised, and the dorsal surface appears flattened or 

 straight, while the ventral surface is curved. The character- 

 istic feature that distinguishes this species from others is the 

 very long, thin posterior portion. 



Abnormal forms. 



In a specimen of Limnodynastes dorsalis coming from Heath- 

 cote, Vic, I found numerous forms of Opalinae varying in shape 

 and also in the number of nuclei present. Their outlines as 

 drawn with the camera lucida are represented in Plate LXX., Fig. 

 5. They measured from 120 ^t to over 2 iO/x in length, and I 

 think must be regarded as abnormal forms, in which the nuclei 

 have divided irregularly without the body dividing. They 

 possess nuclei from two to eight in number, which do not seem 

 to be arranged in any definite order. Some of them may repre- 



