210 



BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



M easureme7its of a good-sized individual with 233 nuclei. — Length 

 of body 0.24 mm. ; width of body 0.135 mm. ; thickness of body 0.015 

 mm. ; diameter of nucleus 0.003 mm. to 0.0041 mm. ; diameter of en- 

 dosphenile 0.002 mm. ; cilia line interval, anterior 0.0025 mm., pos- 

 terior 0.004 mm. 



The broadest individuals of these infections seem almost ranm^wny- 

 like in form, but others are more slender, approaching some of the 

 shorter forms among the ohtrigona-Wk^ species. It seems a distinct 

 species, but not very sharply demarcated from related forms. 



Fig. 180. — Opalina copei, from Rana copei : a, magnified 460 diameters ; b and c, 



SAMPLE animals SHOWING THE RANGE OF SIZH AND FORM IN EACH OP TWO INFECTIONS, 

 X 117 DIAMETERS. 



Ojmlina copei^ United States National Museum specimen No. 

 16587 (fig. 181, p. 211). 



Host. — Rana pretiosa Baird and Girard, three good infections, 

 from Montana. The type infection is from United States National 

 Museum specimen No. 17588, 72 mm. long, from Elliston, Montana, 

 July 21, 1891 ; B. W. Evermann, collector. 



Measurements of a large individual. — Length of body 0.273 mm.; 

 width of body 0.13 mm.; thickness of body 0.0145 mm.; diameter of 

 nucleus 0.004 mm. to 0.0055 mm.; diameter of endospherule 0.002 

 mm. ; cilia line interval, anterior 0.0018 mm., posterior 0.00306 mm. 



Though these infections are from a different species of host and 

 from a very different locality, they seem to belong to Opalina copei. 



