DIFFLUGIA ACUMINATA. 21 



2, p. 13; and XX (1901), 8, p. 12; LONGHI in Atti Soc. 

 Ligust. Ill (1892), p. 145; SCHEWIAKOFF in Mem. Acad. 

 St. Petersb. (7), XLI (1893), 8, p. 98; ZACHARIAS in 

 Forschb. biol. Stat. Plon, I (1893), p. 3 ; and op. cit. II 

 (1894), p. 57; ZSCHOKKE in Verh. nat. Ges. Basel, XI, 1 

 (1895), p. 43 etc. ; BARROIS in Mem. Soc. Sci. Lille, (5) 

 VI (1896), p. 118 etc.; FRANCE in Res. wiss. Erforsch. 

 Balatons. II (1897), 1, pp. 3, 8 ; FUHRMANN in Rev. Suisse 

 Zool. IV (1897), p. 491 etc. ; SCHAUDINN in Deutsch-Ost- 

 Africa, IV, 2 (1897), 19, p. 9 ; ANDRE in Jahresb. nat. Ges. 

 Graubiind. XLI (1898), pp. 58, 59; HBMPEL in Bull. 

 Illinois State Lab. V (1898), p. 319; STENROOS in Acta 

 Soc. Fauna Fenn. XVII (1898), 1, p. 33 etc. ; AVERINTZEV 

 in Trndui S.-Peterb. Obshch. XXX, 1 (1900), p. 239 ; op. 

 cit. XXXVI (1906), 2, p. 192 ; and in Ber. Siisswass. nat. 

 Ges. St. Petersb. 1 (1901), p. 212; GODET in Bull. Soc. 

 Neuchatel, XXVIII (1900), p. 77; LAGERHEIM in Forh. 

 Geol. Foren. Stockholm, XXIII (1901), p. 509 etc. ; G. S. 

 WEST in Jrn. Linn. Soc., Zool. XXVIII (1901), p. 319; 

 KOPOID in Bull. Illinois State Lab. VI, 2 (1903), p. 526; 

 ZYKOFP in Bull. Soc. nat, Moscou, XVII (1903), p. 15; 

 FOREL Le Leman, III (1904), p. 138; GOLDSMIDT in Arch. 

 Protist. V, 1 (1904), p. 131 ; 'SCHORLER & THALWITZ in 

 Ann. Biol. Lacustre, I (1906), pp. 260, 286; SCHOUTEDEN 

 in Ann. Biol. Lacustre, I, 3 (1906), pp. 343, 346; THIEBAUD 

 & FAVRE in Ann. Biol. Lacustre, I, 1 (1906), p. 76 etc.; 

 BREHM in Arch. Hydrobiol. II, 4 (1907), p. 473 ; SCHNEIDER 

 in Arch. Biontol. II (1908), 1, p. 57. 



Difflugia acaidls PERTY in Mitth. nat. Ges. Bern, 1849, p. 167. 



Difflugia acuminata var. acauli* PERTY Kenntn. kleinst. 

 Lebensf. (1852), p. 186, t. ix, f. 6; LONGI in Atti Soc. 

 Ligust. Ill (1892), p. 145; and op. cit. V (1894), p. 19. 



Difflugia mitriforniis var. acuminata WALLICH in Ann. Nat. 

 Hist. (3) XIII (1864), p. 240, t. xv, ff. 3 a-c ; t. xvi, f. 11. 



Test usually oblong, oval, pyriform, or sub-cylin- 

 drical, somewhat enlarged posteriorly ; three to four 

 times longer than broad ; the crown tapering or acumi- 

 nate ; the neck narrowing slightly to a rather wide 

 circular mouth. Surface of the test rarely smooth, 

 more frequently carrying an incrustation of sand- 

 grains, occasionally with diatoms intermixed. Proto- 

 plasm colourless; nucleus and pseudopodia as in the 

 allied species. 



