52 BRITISH FRESHWATER RHIZOPODA. 



Ill ditches and ponds, not common. Richmond 

 Park, Surrey, associated with JJ. urceolata and other 

 forms. Epping Forest, Essex {D. J. Scourfield). 

 Llyn Llydaw, and pools on y Foel Eras, N. Wales ; 

 also in the Hebrides {G. S. West). 



A very distinct species, smaller than D. urceolata 

 Carter, but larger than D. lobostoma, Leidy, from 

 which it differs in size, in the character of the mouth, 

 and in the spined crown. The latter species rarely has 

 a mouth more than four-lobed, and taking all the 

 characters into account there does not seem any 

 ground for supposing that the two species {D. corona 

 and B. lobostoma) are specifically related, however 

 much the form of the mouth might suggest it. 

 D. corona is the handsomest species of the genus. 



21. Difflugia oviformis sp. nov. 



(Plate XX, figs. 8-12.) 



Difflugia lobostoma Leidy (pars) Freshw. Rliiz. N. Amer. 

 (1879), p. 112, t. XV, ff. 16, 17. 



Test ovoid, beautifully symmetrical and smooth, with 

 a broadly-rounded crown not compressed, the sides 

 curving gracefully downwards to the rather narrow' 

 (usually) quadrilobate mouth which is furnished with 

 an expanded wavy collar of thin chitinoos substance 

 and has a wavy outline, following the sinuosities of the 

 aperture, which is rarely five-lobed. The whole struc- 

 ture lightish-brown in colour, getting darker with age, 

 covered externally Avith elongated rectangular scale- 

 like particles, thickly and irregularly set, watli little or 

 no incrustation of any other kind. The plasma, visible 

 through the test-walls, not entirely filling the cavity ; 

 connected with the fundus by threads of ectoplasm. 

 The nucleus single, situated posteriorly ; pseudopodia 

 numerous, colourless, simple or sparingly branched. 



Dimensions : Length 110 /u; breadth 80 /a. 



In wet moss at pond sides and on trees near the 

 water's edge, Clielford, Cheshire. 



