116 BRITISH fllESHWATEB KHIKOPODA. 



Penaed in Mem. Soc. Geneve, XXXI, i, ii (1890), p. 170, pi. vii, ff. 

 11.5-117 ; pi. viii, ff. 1-7 ; in Jahrb. nassau. Ver. Naturk. XLIII 

 (1890), p. 71. 

 Rhumbler in Zeits. wiss. Zool. LXI (1895), p. 95. 

 Dblage & Heeouakd Traite Zool. concrete, I (1896), p. 115. f. 151. 

 Plagiophrys gracilis 



Pbnakd in Mem. Soc. Geneve, XXXI, i, ii (1890), p. 173, pi. viii, 



ff. 43-45; in Rev. Suisse Zool. YII (1899), p. 60, pi. vii, f. 37. 

 Thibbatjd & Pavkb in Ann. Biol, lacustre, I (1906), pp. 68, 76. 

 Pseudodifflugia hemisphxrica 



Penabd in Amer. Natur. XXV (1891), p. 1083. 

 Difflugia urceolata 

 Peancb (pars) in Res. Erforsck Balatons. II, i (1897), p. 7. 



Test liglit brown or yellowisli in colour, broadly 

 ovoid or sub-spherical; covered v^itli fine quartz-grains ; 

 not compressed; aperture circular, terminal, devoid 

 of neck; nucleus placed posteriorly; a small contractile 

 vesicle sometimes discernible; pseudopodia long, filose, 

 straight or forked. 



Length 30-55 /x ; aperture 10-20 /a. 



Habitat. — Aquatic vegetation. 



England. — -N. Yorkshire ; Cheshire (Gash) ; Shrop- 

 shire ; Bedfordshire ; Essex (Scourfield) ; Bucking- 

 hamshire ; Isle of Wight ; Devonshire ; Cornwall. 



Wales.- — Llyn Bochlwyd and Capel Curig, Carnar- 

 vonshire (West). 



Scotland. — Shetlands; Outer Hebrides; Inverness- 

 shire (Brown). 



Ireland. — Clare Island, Mayo ; Wicklow (Archer). 



Between the limits of length (20-65 jjl) indicated by 

 Penard are a number of forms which show considerable 

 variation in colour, relative size of aperture, and the 

 character of the adherent foreign particles as well as 

 in the appearance of the pseudopodia. The larger 

 sub-spherical forms appear to be rare in the British 

 Isles, the type usually found being broadly ovoid and 

 of rather small size (30-40 /x in length). 



This species is distinguished from P. fulva by its 

 larger size and the usually comparatively smooth ex- 

 terior of its test; the character of the pseudopodia and 

 colour of the test distinguish it from species belonging 

 to the genera Difflugia and Fhryganella. 



