DIFFLUGIA CORONA. 51 



SCHOUTEDEN in Ann. Biol. Lacustre, I, 3 (1906), pp. 344, 

 348, f. 21 ; ZSCHOKKE in Arch. Hydvobiol. II, 1 (1906), 

 p. 3; LEMMERMANN in Arch. Hydrobiol. II, 4 (1907), p. 

 537 ; SKORIKOV in Bull. Acad. Sci. St. Petersb. (6) I 

 (1907), pp. 124, 125, etc.; HOOGENRAAD in Tydschr. 

 Xederl. Dierk. Ver. (2) X, 4 (1908), p. 407 ; LANDACRE in 

 Pr. Davonport Acad. Sci. IV, 10 (1908), p. 428. 



Corona cornula VEJDOVSKY in Sitzber. bohm. Ges. Wiss. 1880 

 (1881), p. 137. 



Difflugia acuminata var. furcata DADAY in Termesz. Fuzetek, 

 XV (1892), p. 32, t. i, f. 2. 



Test ovoid, inclining to spheroid, in transverse, or 

 oral view, circular ; with a broadly-rounded crown fur- 





FIG. 65. A peculiar form of Difflugia corona with rounded spines and 

 a large aperture, from Llyn Llydaw, Snowdon. From a drawing 

 by G. S. West, x 200. 



nished with a variable number of conical spines ; 

 narrower at the mouth (which in the side view is more 

 or less convex) ; the mouth central, circular, its 

 border multidentate, or multilobate, with a variable 

 number of small, but perfectly regular divisions, num- 

 bering from 12 to 20. Structure of the shell, as in 

 D. lobostoma Leidy, incrusted with fine sand -grains, 

 and opaque. Protoplasm colourless ; the pseudopodia 

 numerous, long and rather thin, with a tendency to 

 branch or bifurcate. 



Dimensions: Length 1 80*230 /i ; breadth about 



150 



