176 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



Ryla arborea^ 16534 from Hyla arhorea japonica, 16535 from Hyla 

 arborea savignyi. 



Hosts. — Hyla arborea (Linnaeus), reported by many observers; 

 my material includes many infections studied in Germany : Hyla 

 arborea japonica Schlegel, one infection from Japan, in United 

 States National Museum specimen No. 23907, 32 mm. long, I. Ijima 

 collector, and one infection from United States National Museum 

 specimen No. 52354, 35 mm. long, from Yulu Eiver, southern Man- 



FlO. 



142. — Opalina obtuigona, X 117 diameters. In one figure is drawn 



LINE OF INSERTION OF A ROW OF CILIA TO INDICATE ITS SPIRAL CODRSB. 



churia, A. de C. Sowerby collector (but one small clump of Opalinae 

 was seen in this last infection and they were not studied enough to 

 make the identification certain) ; Hyla arborea savignyi Audouin, 

 one infection in United States National Museum specimen No. 37190, 

 40 mm. long, from Jerusalem, AVerner collector. 



Measurements of an average individual frotn Hyla arborea. — 

 Length of body 0.483 mm. ; width of body 0.154 mm. ; thickness of 

 body, anterior 0.034 mm., middle 0.0345 mm., posterior 0.037 mm.; 

 diameter of nucleus 0.00675 mm. to 0.009 mm.; diameter of endo- 

 sphenile 0.0015 mm. (some were elongated, 0.0015 mm. b}^ 0.0025; 



