THE OPALINID CILIATE INFUSORIANS. 

 OPALINA RANARUM, form CINCTOIDEA, new forma (figs. 200, 201). 



227 



Type. — United States National Museum Cat. No. 16595. 



Host. — Rana temporaria^ from Wiirzburg (?), Germany, January 

 14, 1908.— These were purchased frogs, and the locality is uncertain. 



Measurements of an ordinary individual. — Length of body, 0.243 

 mm.; width of body, 0.185 mm.; thickness of body, anterior 0.02 

 mm., middle 0.021 mm., posterior 0.02 mm.; diameter of nucleus, 

 0.0065 mm. to 0.01 mm.; length and width of endospherule, first 

 0.002 mm. by 0.0011 mm., second 0.0015 mm. by 0.0015 mm.; cilia 



Fig. 201, — Opalina eanabdm, foem cinctoidea : a, a geodp of animals from one infec- 

 tion, SHOWING RANGE OF SIZE AND FORM^ X 117 DIAMETERS ; 6, AN INDIVIDUAL OF THE 

 USUAL SORT;^_ X 460 DIAMETERS. NOTE THE FINELY GRANULAR, RETICULATE CONDITION 

 OF THE MACROCHBOMATIN, IN CONTRAST TO THE CONDITION SHOWN IN FIGURE 200. 



line interval, anterior 0.0028 mm., posterior 0.0042 mm. ; interval be- 

 tween finest longitudinal striae, 0.0009 mm. 



The ordinary individuals in these infections are short and broad, 

 though some are narrower. The posterior end is broadly rounded, 

 or almost truncate. The morphological anterior end is bent to one 

 side, as in all other forms, its distal edge forming the pointed actual 

 anterior end. The ectosarc is very wide around the whole con- 

 tour of the body, and there is no special thickening of the mor- 

 phological anterior edge, nor any marked crowding of nuclei or 



