THE FRESHWATER ALG OF CEYLON. 145 
Long. 768,5; lat. ad bas. semicell. 44u; lat. apic. semicell. 25 u. 
Hab. In small pond, Peradeniya. 
Forma minor, cellulis paullo angustioribus. Long. 577,4; lat. ad bas. semicell. 23 4; 
lat. apic. semicell. 13:5 u. 
Hab. In artificial tank, Peradeniya. 
Var. cRASSIUS, Lagerh. in Botaniska Notiser, 1886, p. 199. 
Long. 462,4; lat. ad bas. semicell. 46; lat. apic. semicell. 28 u. 
Hab. With the typical form, Peradeniya. 
96. PLEUROTHNIUM EmnnEkNnBEnGIL, De Bary, Conj. 1858, p. 75. Docidium Ehren- 
bergit, Bréb. 1844; Ralfs, Brit. Desm. p. 157, t. 26. fig. 4. 
Hab. Paddyfields, Heneratgodha. Paddyfield between Kosgoda and Urahaighasma- 
hendai. 
Var. UNDULATUM, Schaarschm. in Magyar. Tudom. Akad. math. és Termész. 
Közlemények, vol. xviii. 1882, p. 278, t. 1. fig. 21. 
Long. 345 4; lat. ad bas. semicell. 224; lat. apice. semicell. 14 4. (P1. 18. fig. 28.) 
Hab. In artificial tank, Peradeniya. 
The form observed certainly belongs to P. Ehrenbergii, and the lateral margins are 
gently undulate from base to apex; but, although it is of the normal size of a specimen 
of P. Ehrenbergii, it is only about half the size of the plant described by Schaarschmidt 
as P. Ehrenbergii, var. undulatum. It is quite probable that the plant described and 
figured by Schaarschmidt does not belong to P. Ehrenbergii. 
Var. Boport, var. pn. (Pleurotenium basiundatum, West & G. S. West, forma diametro 
17-19-plo longior, apicibus attenuatis, Borge, in Bih. till K. Sv. Vet.-Akad. Handl. 
1896, xxii. Afd. 3, no. 9, p. 26, t. 3. fig. 46.) Var. semicellulis paullo angustioribus, 
undulis parvis circ. 4 supra inflationem basalem. 
Long. 368,4; lat. ad bas. semicell. 19 4; lat. apic. semicell. 11:5 4. (Pl. 18. fig. 27.) 
Hab. Paddyfield between Kosgoda and Urahaighasmahendai. 
This plant bears little resemblance to P. basiundatum, West & G. S. West. 
97. PLEUROTHZNIUM MAXIMUM, Lund. in Nov. Act. Soc. Sci. Upsala, ser. 3, viii. 1871, 
p. 89. Docidium maximum, Reinsch, in Abhandl. Senckenb. naturforsch. Gesellsch. 
vi. 1867, p. 140, t. 27. figs. 1-2; in Abhandl. naturhist. Gesellsch. zu Nürnberg, 
iii. 1866, p. 184, t. 17. fig. 4. Pleurotenium Archerii, Delponte, in Mem. Accad. 
Sci. Torino, ser. 2, xxx. 1877, p. 128, t. 19. figs. 12-16. 
Long. 568,4; lat. ad bas. semicell. 424; lat. ad med. semicell. 32-33 u; lat. ad apic. 
semicell. 27 u. 
Hab. Pond, Victoria Park, Colombo. 
We fail to see any difference between P. maximum and P. Archerii. Both so-called 
