160 \V. B. TURNER, FRESH-WATEK ALGM OF EAST INDIA. 



Wallich Mscr. No. 313, ex. p. 



Frond long. et lat. '27; sp. inelus. 57 X 50 ,w. T. XX, f. 17. 



3. P. simplex, Meyen, Nied. Alg. p. 772, t. XLIII, f. 1—5, 1828; Braun Unic. Alg. p. 



80; Rkixsoh Alg. Frank. t. VII, f. 4. 

 Walltch Mscr. No. 314, f. 1. 

 In Wallich 1. c, No. 314, 1'. 11, there is a form of this with 9 rävs = 4 + 9. 



4. P. incavatuin, n. sp. 



This small form, of about 22 — 28 /* diameter, seems to differ in its incavate 

 apices from any I have observed. Wallich gives it in liis Mscr. No. 314, f. 7. 

 T. XXI, f. 21, after G. C. W. 

 Diam. 22—28 /u. 



5. P. gracile, Al. Braun, Unic. Alg. p. 92; Reinscii Alg. Frank. p. 94, t. VII, f. 2; 

 forma bidentata. 



Form exactly, as in Reinsch's fig., hut minutely bidentate at the apices. Wal- 

 lich Mscr. No, 305. 



Diam. circ. 40 ju. T. XX, f. 10 X 700. 

 0. P. rotula, KiTZ. Phyc. Germ. p. 143, No. 8; Näg. Einz. Alg. p. 95, t. V B, f. 3b; 

 non Braun, 1. c t, VI, f. 1 — 14! 



This much resembles the figure of Nägeli 1. c, but the apices of the cellules 

 on each side of the incision are squarely truncate. Wallich Mscr. No. 302, f. 1. 



7. P. selemea, Kltz. 1. c, No. 4; Ralfs Br. Desm. t, XXXI, f. 5?; Näg. 1. c B, f. 2. 



Wallich Mscr. No. 300, 302. (302 = 1 + 7 -f 13 + 15). 



8. P. Boryanum (Turp.) Mexgii. Synops. p. 210; Helierella Bort/tina, Turp. Mem. Mus. 

 XVI, p. 318, 1827; Micrast. Boryana, Ehrb. Abhl. p. 390, 1833; fide Braun; Racib. 

 Ped. p. 12, 1889. 



Wallich Mscr. No. 304 = 1 + 5 + 11 + 15. 

 Long. 90, lat. 76 /u. G. C. W. 



9. P. constrictuin, Hassall, Fr. Alg. p. 391, t. 86, f. 15, 16, 1845; Racib. Pediast. p. 

 30, t. II, f. 44; P. ellipticum Ralfs ex p. Br. Desm. t, XXXI, f. 10 d. 



Wallich Mscr. No. 312, a b, (both a et b, 5 + 11). 



Long. 41, lat. 36 /u. G. C. W. 

 K). P. duplex, Meyen, 1. c. p. 772, 1828; f. asperum (/'. pertusum rar. s asperum) 

 Braun 1. c. p. 93; Racib. Pediastr. p. 25. 



Wallich Mscr. No. 298 (1 + 5 + 11 + 14!) 



Fröns circularis; diam. 98 /u. 

 11. P. sp. formae; after Wallich Mscr. 



T. XX, f. 12; W. No. 314, f. 3 — f. 13; W. No. 314, f. 4. 



Forman cellulis confusis; inevolutis? 



Pediastra of curious form (undeveloped?) are not uncommon in gatherings in 

 which the genus is Avell represented. In Meyens original meuioir (1828), lie notices 

 such forms under S. duplex Mey., f. 16, 17. 



Various Pediastra in Wallichs Mscr. are not determined. 



