204 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



mm. to 0.0017 mm. ; cilia line interval, anterior 0.0016 mm., middle 

 0.00175 mm., posterior 0.0025 mm. 



Nearly all individuals in this species are much curved, with often 

 an abruptly enlarged anterior end. They resemble in form the 

 comma-shaped individuals of O. pickeringii, except that the latter 

 are more slender. The nuclei are almost all spherical and run much 

 smaller than those of O. plckerinr/ii. 



i 



Fig. 173. 



-OPALINA VIRGULOIDEA, FKOM RANA BOYLEI, X 117 DIAMETERS : a AND b ARD 

 FROM DIFFERENT INFECTIONS. 



Opalina virguloidea, United States National Museum No. 16615. 



Host. — Rana hoylei Baird and Girard, numerous living infections 

 from frogs purchased in San Francisco, California, April 3, 1913, 

 said to have been collected near San Francisco. 



Measurements of a rather large individual. — Length of body, 0.34 

 mm.; width of body, 0.11 mm.; thickness of body, anterior 0.0105 

 mm., middle 0.0115 mm., posterior 0.013 mm.; diameter of nucleus 



