182 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



to 0.006 mm. (mean 0.0043 mm.) ; diameter of endospherule, 0.00175 

 mm. to 0.0025 mm.; cilia line interval, anterior, 0.00183 mm., middle, 

 0.00375 mm., posterior, 0.00635 mm. 



The cilia are unusually scant on the posterior part of the body 

 of this Opalina^ but the intervals between the lines of cilia are not, 

 in general, dependable diagnostic characters, for they vary too much 

 with the individual, but such an extreme interval between the cilia 

 lines posteriori}'', and such difference between the anterior and the 

 posterior ends of the body in cilia line -interval, is noteworthy. 



Opalina ohtHgonoidea, United States National Museum No. 16550. 



Host. — Gastrofhryne carolinense (Holbrook), one infection from 



Georgia, and another, the type, from United States National Museum 



specimen No. 48894, 28 mm. long, from 



Charlesburg, Virginia, July 22, 1910; F. P. 



Drowne, collector. 



Measurements. — Length of body, 0.2 mm.; 

 width of body, 0.085 mm.; diameter of nu- 

 cleus, 0.0044 mm. to 0.0055 mm. (mean, 

 Fig. 149.— orALiNA oBTRiG- 0.0047 mm.); diameter of endospherule, 

 phkyne' cakolinb.xse, X 0.0018 mm. ; cilia line interval, anterior 0.00185 

 117 DIAMETERS. mm., postcrlor 0.00375 mm. 



Opalina ohtrigonoidea, United States National Museum No. 16555, 

 (figs. 150 and 151). 



Host. — Rana pipiens Schreber, many infections, from Oberlin, 

 Ohio, Ealeigh, North Carolina, and Chicago, Illinois. 



Measurements of a large individual. — Length of body, 0.453 mm. ; 

 width of body, 0.154 mm. ; thickness of body, anterior, 0.0175 mm., 

 middle, 0.018 mm., posterior, 0.019 mm. ; diameter of nucleus, 0.0045 

 mm. to 0.0058 mm. ; diameter of endospherule, 0.0022 mm. to 0.0026 

 mm. ; cilia line interval, anterior, 0.0018 mm., posterior, 0.00287 mm. 



Many of the individuals in these infections are broader than typi- 

 cal Opalina ohtrigonoidea from Bufo fowleri; others are of the typi- 

 cal form. 



Opalina ohtiigonoidea, United States National Museum specimens 

 Nos. 16560 and 16561 (figs. 152 and 153). 



Host. — Rana palustris LeConte, many living infections from Woods 

 Hole, Massachusetts, and from Oberlin, Ohio. 



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