56 



BULLETIN 120, UNITED STATES NATIONAL MUSEUM, 



ever, having distinct walls and a clear lumen, 

 condition is, however, that shown in figure 30, h. 



The characteristic 



PROTOOPALINA HYLARUM (Raff). 



Opalina hylarnin Raff (1911). 



Host. — Hyla aurea (Lesson), from Australia. 



Raff's original description is copied in full : 



Opalina hylarum, n. sp., occurs in Hyla aurea only, and is distinguished from 

 all the other binucleated forms which are circular in cross section by its 

 enormous size. It measures on an average about 420 fi, but some individuals 

 measuring as much as 572 fi have been met with. The average breadth is 70 ft. 

 The body is elongatedly oval, with a rounded anterior end and a slightly 

 rounded posterior extremity — i. e., it does not taper to a point posteriorly. The 

 protoplasm is granular, and ectosarc and endosarc are clearly distinguishable 

 right to the posterior end [not an unusual feature, ti'ue of nearly all Opalinids]. 

 A very well-marked feature of this species is the position of the nuclei, for they 

 are placed far apart, the hinder one being in the posterior half of the body. 

 The chromatin material is gathered into masses arranged around the periphery 



a 



Fig. 31. — Protoop.\lina htlardm. (After Raff.) 



of the nucleus. This is well shown in the transverse section represented in 

 fig. 11 [omitted here]. The body is ciliated round its entire surface, the cilia 

 at the anterior end being slightly longer than those towards the posterior end, 

 but there is no portion devoid of cilia. 



Some individuals showed only a ?ingle nucleus, in difierent stages of division, 

 but these are the results of recent longitudinal division. In figures 12 to 14 

 [omitted here] the outlines of three specimens are shown with the positions 

 of the nuclei indicated. In figures 12 and 13 [omitted here] the daughter 

 nuclei have not yet separated, while in figure 14 [ondtted here] division of 

 the nucleus is completed and the nuclei have taken up their adult position. 



In the posterior portion of the body excretory organs are present in the form 

 of a great number of vacuoles, forming quite a network and extending from 

 about the middle of the body to the posterior extremity. 



This is beyond question a distinct species. 



PROTOOPALINA FILIFORMIS, new species. 



Type. — United States National Museum Cat. No. 16444, also 

 paratype No. 16445. 



Host. — Rana tigerina Daudin, two infections, from United States 

 National Museum specimen No. 38219, 69 mm. long, the type in- 



