THE OPALINID CILIATE INFUSOKIANS. 



177 



mm.) cilia line interval, anterior 0.0025 mm., middle 0.00475 mm., 

 posterior 0.00475 mm. 



This large, well-known Opalina has the characteristic form shown 

 in the figures. Occasional anterior daughter cells, fresh from trans- 

 verse division, are less slender behind. The more slender forms 

 shown in the figures are probably recent products of longitudinal 

 fission. The nuclei are large, being almost as large as in Zelleriella 

 microcarya^ which has the smallest nuclei of the laiown binucleated 

 species. 







Fig. 142, A. — Opalina obtrigona, X 460 diameters : a, anterior end, the fink tarai*- 



LEL LINES REPRESENTING LINES OF INSERTION OF CILIA ; 6, A BIT OF THE SIDE OF THE 

 BOOT SHOWING COARSER ALVEOLATION OF THE BCTOSARC, THE ENDOSPHERULBS, BEING 

 DRAWN IN THIS FIGDRE. 



My material from the subspecies japonica and savignyi is not in 

 good condition for detailed study. The infections in both cases seem 

 to belong to the species ohtrigona. 



OPALINA OBTRIGONOIDEA, new species. 



Type. — United States National Museum Cat. No. 16536. 



Host. — Bufo fowleri Putnam, numerous living infections from 

 Woods Hole, Massachusetts. The type infection was collected July 

 28, 1919, by M. M. Metcalf. 



Measurements: A., of a large individiial; B, of a small individual — 



Length of body 

 Width of body 

 Thickness of body 

 Diameter of nucleus 

 Diameter of endospherule 



