DIPFLUGIA 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; Zachaeias in 

 Porschb. bioi. Stat. Plon, I (1898), p. 3 ; and op. cit. II 

 (1894), p. 57; ZscHOKKE in Verli. nat. Ges. Basel, XI, 1 

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

 VI (1896), p. 118 etc.; Feancb in Res. wiss. Brforsch. 

 Balatons. II (1897), 1, pp. 3, 8 ; FuHEMANNin Eev. 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; Hempel in Bull. 

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

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

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

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

 Ges. St. Petersb. I (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; 

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

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

 Foeel Le Leman, III (1904), p. 138; Goldsmidt in Arch. 

 Protist. V, 1 (1904), p. 131 ; Schoelbe & Thalwitz in 

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

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

 & Favee iu Ann. Biol. Lacustre, I, 1 (1906), p. 76 etc.; 

 Beehm in Arch. Hydrobiol. II, 4 (1907), p. 473 ; Schneidee 

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



Difflugia acanlis Perty in Mitth. nat. Ges. Bern, 1849, p. 167. 



Difflugia acuminata var. acaulis Perty Kenntn. kleinst. 

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

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



Difflugia mitriformis 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. 



