44 



BULLETIN 120, UNITED STATES NATIONAL MUSEUM, 



1i 



infection, and 5, United States National Museum specimen No. 37193, 

 from Eastern Algeria (for its Opalinid see United States National 

 Museum Cat. No. 16437). 



Measurements. — Length of body 0.1469 mm. ; width of body 0.0254 

 mm. ; length of nucleus 0.013 mm. ; width of nucleus 0.0087 mm. ; 

 diameter of endospherule 0.0024 mm. ; cilia line interval, anterior 

 0.00125 mm. ; middle 0.0035 mm. ; posterior 0.0035 mm. 



These animals are shaped in general like P. intestinalis, but pos- 

 teriorly they end in a distinct point, or more often in a short " spine " 

 which is often curved as it is in P. 7nacrocaudata, still to be described. 



Fig. 21. — Protoopalina caddata discoglossi. X 460 diambteks. 



They resemble also some of the intermediate forms of P. caudata, 

 but have more numerous cilia over the anterior end of the body 

 (not shown in the figures), and their nuclear conditions are more 

 diverse. Two distinct nuclei are most usual, and these lie quite far 

 back in the body. In individuals recently come from division, the 

 nuclei are united by a thread, or we may even find cases of dumb-bell- 

 shaped nuclei, with the constriction very marked. None of my 

 material is well enough preserved to allow counting the chromosomes. 

 Protoopalina caudata has not been reported from Discoglossus^ 

 but P. intestinalis has. It is possible that the form here described 

 is the one that has been reported as P. intestinalis. 



