DIFFLUGIA CORONA. 51 



ScHOUTEDEN in Aiiii. Biol. Lacusti-e, I, 3 (1906), pp. 344, 

 348, f. 21 ; ZscHOKKE in Arch. Hydrobiol. II, 1 (1906), 

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

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

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

 Nederl. Dierk. Ver. (2) X, 4 (1908), p. 407 ; Landacbe in 

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



Corona cornida Vejdovsky in Sitzber..b6hm. Ges. Wiss. 1880 

 (1881), p. 137. 



Diffliogia acuminata var. furcata Daday in Termesz. Piizetek, 

 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 (Avhich 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 1 2 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 180-230 ^i; breadth about 

 160^. 



