K0NGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 159 



Gen. 3. Staurophanum, n. g. 

 Fruns plus minus cruciforinis, normäliter 4-partita, vel 4-lobulata, ad fines aut 

 sillgula aut furcata, angulis vel non productis; anguli interiores rotundati; apicibus 2 — 3 

 dentatis vel cuspidatis; a latere visa lanceolata, finibus plus minus attenuatis. 



1. S. crnciatum (Wallich) Nob. Micrasterias cruciata, Wall. Desm. Beng. p. 281, t. 

 XIII, f. 12, 1860; G. C. W. Mscr. No. 83. 



F. majus, n. f. Long. et lat. 48—54 t u. T. XX, f. 21, X (570. 



F. minus, n. f. » » 24—28 ,u. T. XX, f. 20, » 

 Bengal; Central India. 



2. S. pusillum (Wallich) Nob. Micrasterias pusilla^ Wallich 1. c., t. XIII, f. 13; Mscr. 



No. 80. Both this and the preeeding are bluntly-lanceolate in lat. view. 



Long. et lat. 25, crass. 10 fi. T. XX, 1'. 22. 



Under this genus, which is allied to Polyedrium, Näg., I would (whilst not in- 

 terfering with Polyedria genuina?) include such stauriform and lobate plants as the P. 

 gracile of Reinsch, Monogr. Polyedr. p. 502, t. VII, f. 1 (St. gracile (Rnsch) Nob.). 



Gen. 4. Thallodesmium, n. g. 

 Plantula minuta (plana?) sub-orbicularis, in stratum gelatinosum tenue nidulans vel 

 libere natans; ex eellula unica margine sinuata vel incisa pilis rectis brevibus instructa, 

 medio profunde constricta, constituta. Massa* chlorophyllacea) irregulares, sub-radiatim 

 dispositis. 

 1. T. Wallichianuni, n. sp. 



Under this I give a little plant of very uneertain loeation, which at first sight 

 looks like a Desniid. Dr. Wallich, in Mscr. No. 327, says, »Composed of 2 nearly 

 identical segments. The general outline is jagged and sinuous, exhibiting an inciso- 

 lobate appearance, the edges being furnished with short straight hairs. Constriction 

 though not symmetrical is well marked. The endochrome is in irregular masses, 

 disposed somewhat radially; it is more yellowish-green than usual in these organisms. 

 The form is the normal one, and seems to be sub-symmetrical.» 



Long. 39—52, lat. 33—45 ,«. T. XX, f. 31, after Wallich; X 450. 

 Bengal; common, G. C. W. 



This plant is very peculiar, and seems to be a small aquatic thallophyte. I 

 would propose the above name for such a unique form on account of its pseudo- 

 Desmidian appearance. 



Ord. III. PEDIASTRE.E, Naeg. 



Gen. 1. Pediastrum, Mhyen, Nied. Alg. p. 772, 1828! 



(Micrasterias, Ennn. et Kltz. ex. p. 1831 — 1840; non Agdii. 



1. P. tetras (Eiirb.) Ralfs in Annals, p. 469, t. XII, f. 4, 1844 ex. p.; Micrasterias 

 tetras, Ehrb. Inf. p. 155, t. XI, f. 1; Pediastrum Ehrenbergii (Corda) A. Br. Unic. 

 Alg. p. 97, t. V, H f. 2. 



In Wallich Mscr. No. 310; diam. 20 //. 



Forma 1 — {— 7, Braun 1. c. H, f. 4; Wallich Mscr. 303 d; diam.? 



2. P. Sturmii, Reinsch, Alg. Frank. p. 90, t. VII, f. 1 b; forma. 



