138 BRITISH FRESHWATER RHIZOPODA. 



Rhiz. Leman (1902), p. 382, ff. 1-6; in Arch. Protist. II 

 .(1903), p. 257 ; in Pr. R. Soc. Edinb. XXV, 8 (1905), pp. 

 594, 596 ; and in Jrn. R, Micr. Soc. 1907, p. 277 ; CASH 

 in Tr. Manch. Micr. Soc. 1891 (1892), p. 51, t. ii, ff. 19, 

 20, 30; LEVANDER in Acta Soc. Fauna Fenn. XII (1894), 

 2, p. 21 ; op. cit. XVIII (1900), 6, pp. 72, 77 ; and XX 

 (1901), 8, pp. 8, 11; SCOURFIELD in Pr. Zool. Soc. 1897, 

 p. 788; LAGERHEOI in Forh. Geol. Foren. Stockholm, 

 XXIII (1901), p. 514 etc. ; G. S. WEST in Jrn. Linn. Soc., 

 Zool. XXVIII (1901), p. 323; and in Ann. Scott. Nat, 

 Hist. 1905, p. 90; FOREL Le Leman, III (1904), p. 138 ; 

 AVERINTZEV in Trudui S.-Peterb. Obshch. XXXVI (1906), 

 2, p. 256; CDSHMAN in Amer. Natur. XL (1906), p. 373; 

 SCHOUTEDEN in Ann. Biol. Lacustre, I, 3 (1906), p. 357 ; 

 ZSCHOKKE in Arch. Hydrobiol. II, 1 (1906), p. 4 ; LAND- 

 ACRE in Pr. Ohio Acad. Sci. IV, 10 (1908), p. 429. 



Test composed of chitinous membrane, strongly 

 compressed, especially near the mouth, its surface 

 covered with amorphous scales which form a loose 

 reticulation and rarely present an appearance of 

 regularity ; the crown rough with sand - grains of 

 varying size ; the lateral margins straight or slightly 

 convex ; the mouth linear or elliptic, its edges thin, 

 and, during the encystment of the organism, closed 

 and sealed internally. Test subject to much variation, 

 both in size and colour, individuals from one locality 

 often differing considerably from those found else- 

 where ; but in all the mouth (in broad view) has a 

 very modified convex outline, sometimes cut straight 

 across, but more or less rounded at the corners. The 

 plasma, in living individuals, not filling the cavity of 

 the test. The nucleus generally conspicuous, in the 

 upper region of the plasma; pseudopodia numerous 

 and thin, with a tendency to bifurcate or throw out 

 short lateral branches. 



Dimensions : Length 80-100 /a. 



In Sphagnum, in boggy places; most frequent in 

 sub-alpine situations. Abundant in North Wales. 

 Near Widdale Beck, N. Yorks; Hawkshead, Lanes; 

 and near Grlenties, Co. Donegal, Ireland (G. 8. West). 



