216 BULLETIN 120, UXITED STATES NATIONAL MUSEUM. 



Opalina chorophili, U. S. National Museum No. 16572 (fig. 187). 



Host. — Chorophilus feriarum (Baird) , four infections from 

 United States National Museum frogs from North Carolina and 

 the District of Columbia, and many living infections from Raleigh, 

 North Carolina, April; H. H. and C. S. Brimley, collectors. From 

 one of the latter infections were taken the specimens of the Opalina 

 deposited with the United States National Museum. 



Measurements of a long, slender individual. — Length of body 

 0.427 mm. ; width of body 0.077 mm. ; thickness of body 0.023 mm. ; 

 diameter of nucleus 0.004 mm. to 0.005 mm. ; width and thickness 

 of disk-shaped endospherule, first 0.003 mm. by 0.001 mm.; second 

 0.0025 mm. by 0.002 mm.; cilia line interval, anterior 0.00158 mm., 

 middle 0.003 mm., posterior 0.0037 mm. 



Opalina chorophili, from all its hosts, has a very wide ectosarc, ex- 

 cept at the anterior end of the body. (Fig 188.) The slender 

 posterior end of the body is usually more or less twisted. It seems 

 to be distinct from 0. ohtrigonoidea. 



OPALINA HELENAE, new species. 



Ty^e.— United States National Museum No. 16576. 



Host. — Agalychnis helenae Cope, two infections, one from 

 Nicaragua, and the other, the type infection, from United States 

 National Museum specimen No, 29959, 65 mm. long, female with pale 

 eggs 1.75 mm. in diameter, from San Carlos, Costa Rica; Burgdorf 

 and Schild collectors. 



Measurements of an average individuM. — Length of body 0.4 mm. ; 

 width of body 0.1367 mm.; thickness of body 0.034 mm-; diameter 

 of nucleus 0.0035 mm. to 0.0045 mm. ; diameter of endospherule 

 0.0015 mm. to 0.00175 mm. ; cilia line interval, anterior 0.00216 mm., 

 middle 0.0035 mm. 





■O .:0-.;.0V 

 O o o 



b 



Fig. 188. — Opalina helenae: a and 6, magnified 117 diameteks ; c, a bit of thb/ 



BODY MAGNIFIED 460 DIAMETERS. 



There are in these infections wedge-shaped individuals, pointed at 

 the posterior end, "and wider forms. The cilia are long, though not 



