38 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



thickness of body at the level of the nuclei 0.02 mm. ; length of nucleus 

 0.0108 mm. ; width of nucleus 0.0065 mm. ; diameter of endospherule 

 0.002 mm. 



My specimens of this species are less than half as long as those of 

 Raff's Protoopalina dorsalis and they have ellipsoidal instead of 

 spherical nuclei. They resemble P. dorsalis closely in the form of the 

 body, being broad in front, being considerably flattened and having 

 the body spirally twisted. Raff's Protoo'palina acuta has oval nuclei, 

 but its body tapers posteriorly to a slender, elongated point. Protoo- 

 'palina peronii resembles P. dorsalis in body form, while its ellipsoidal 

 nuclei resemble those of P. acuta. It seems intermediate between 

 these two species. There are a few cysts present in the infection so it 

 is probable that material gathered at a different time of year would 

 s^ iw individuals larger than those in our material. 



PROTOOPALINA PELOBATIDIS. new species. 



7^2/^6.— United States National Museum Cat. No. 16429. 



Host. — Pelohates fuscus (Laurenti), United States National 

 Museum si)ecimen No. 37191, 54 mm. long, from Klosterneuburg. 

 Austria, May 1897, F. Werner collector; also No. 16450, 48 mm. long 

 from " Europe," no data. Two other individuals from this locality 

 were opened, but no Opalinids were found. Also two individuals 

 collected at Turin, Italy, were opened without finding Opalinids. 

 These bore no data, but the card bore the words " Roy. Zool. Mus." 

 They were soft and in very poor condition, and this may account 

 for the absence of Opalinids. 



Measurements. — Length of body 0.097 mm. ; Avidth of body 0.0185 

 mm. ; length of each ellipsoidal nucleus 0.0105 mm. ; width of each 

 ellipsoidal nucleus 0.0068 mm. ; diameter of endospherules 0.00175 

 mm.; cilia line interval, anterior end 0.0023 mm., middle of body 

 0.0035 mm., posterior end 0.00375 mm. The number of massive chro- 

 mosomes appears to be 8 or perhaps 10. 



This is a slender species rather similar to Protoopalina intestinalis, 

 but is much smaller and differs in nuclear condition. P. intestinalk 

 has been reported from Pelohates fuscus. Goze's reference (1782) 

 is not sufficient for specific identification, nor is Kent's (1881-82), 

 nor Balbiani's (1887), nor Biitschli's (1887-1889). Indeed, I do not 

 find any reference to P. iyitestinalis from Pelohates which is sufficient 

 to enable us to determine whether the intestinalis-like form reported 

 was true intestinalis, or was the species here described. 



The body is rounded in front. The posterior portion of the body 

 narrows, not gradually but rather abruptly to a rounded point. 

 There is no trace of any posterior " spine." The two nuclei are gen- 

 erally pear-shaped and nearly always connected by a thread. They 

 are apparently always so connected except in individuals just about 



