232 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



Measurements: A., of a large individual; .5, of a long., narrow in- 

 d'/oiduaJ; C, of an average form — 



Measurements. X B \ C 



l.enp;th of body 



Width of body 



Thickness of body; 



.\nterior 



Middle 



Posterior 



Diameter of nucleus 



Diameter of endos])herule 

 Cilia line inter^al: 



Anterior 



Posterior 



Tliis subspecies is almost as varied in shape as 0. ranaruni proper. 

 Like the hitter species it is thickest in front, but the difference in 

 thickness between the two ends is much greater in the several indi- 

 viduals measured than it is in O. ranar^um. The nuclei run smaller 

 than in most O. ranannn., but nuclei as small are found in some in- 

 dividuals of O. ranarmn. The subspecies differs from the species 

 proper in the facts, 1, that its narrower forms differ in shape from 

 both the truncata and the parvipalniatae forms of the species, 2, that 

 the difference in thickness between anterior and posterior ends is 

 greater, and 3, in having nuclei which are smaller even in the largest 

 individuals.-^ These Japanese infections give quite a different im- 

 pression from European infections, and one lias the feeling that they 

 are really different, but the differences are hard to define. I have not 

 made a statistical study of the several dimensions in the Japanese 

 and European infections, but it is evident that the two groups would 

 center about different means. 



OPALINA JAPONICA, new speci:?s. 



Type. — United States National Museum Cat. No. 16.-)99. 



Hoxt. — Rana japonica (Guenther), two infections, from Kochi, 

 Shikoku. Japan, May 11; H. M. Smith collector. The type infec- 

 tion is from United States National Museum specimen No. 31907, 

 48 mm. long. 



Measurements of an ordinary individiiaL — Length of body 0.18 

 mm.; width of body 0.128 mm.; thickness of body, anterior 0.0105 

 mm., middle 0.011 mm., posterior 0.007 mm. ; length and width of nu- 

 clei, first 0.0038 mm. by 0.0038 mm., second 0.004 mm. by 0.004 mm.. 



"A paper by Hegner and Hsiang-Fong Wu (1921). of which, through the kindness of 

 Profrssor IIi>guor, I have seen a copy in advance of its publication, calls attention to the 

 fact that in yovuig Opalinas with few nuclei the nuclei tend to be larger than in older 

 individuals. 



