110 W. B. T1KNKK, FRESH-WATER ALGE OF KAST IXDIA. 



Bras. ]>. 225) asking »Nonne forma S. dilatati»? when speaking of the förra above, 

 yet I think he placed it correctly. I am not sure that it is a form of 1 lie s|)ocies to 

 which I have reférred it. 



Bengal; Northern India. 



(Nos. 26 and 27 should have followed No. 6, being related thereto.) 



28. S. trifurcatum, n. sp. S. mediocre, circa quarta parte latins quam lougura (sp. mel.), 

 quadrangulare; semicellulis late qnadratis, dorso paullo convexis, ventre paullo intiatis; 

 angulis 3, superioribus bitidis, in acnleos duos divergentesprotentis, interne rotundatis; 

 angulis inferioribus quoque aculeum singulum acutum attennatum convergens niunitis; 

 mambrana glabra; sinu acuto, aperto, interne rotundato. A vertice visum triangulare; 

 lateribus in medio paullo convexis, angulos versus paullo constrictis, angulis externe 

 bitido-aculeatis, interne rotundatis. Massa chlorophyllacea radians, apud angulos bisecta. 



Wallich, Mscr. No. 243. 



Var. (i reversum. Angulis superioribus simplicibus uni-aculeatis, inferioribus bi- 

 aculeatis bitidis. Wallich, Mscr. No. 242. T. XVII, f. 9 (/?, after Wallich). 



« and (i long. 35 — 44, lat. 54 — 60 (incl. sp.), lat. isth. 13, long. sp. 11 ju. 

 A 'reversed' form is also found in No. 22 supra. 

 Kaneegunge, Nov. 1855 — rare. G. C. W. 



29. S. Uoergesenii, n. sp. »St. parvum, sub-circulare, quinta parte latins quam longuni; 

 semicellula? reniformes, dorso convexae, basi rotundatas paullo convergentes; semicellulis 

 quinque-lobulatis; membrana glabra?, sinu aperto, sub-sequäle, interne rotundato. A 

 vertice visum stellare; lobulis triangularibus, apicibus acuto-rotundatis. Massa chloro- 

 phyllacea axili, radiata. 



Long. 16—17, lat, 18.5—22, lat. isth. 6 /u. (Also Wallich Mscr. No. 280 B). 

 T. XIII, f. 23 X 300. 



To F. Bökgesex, a Danish botanist and author, I dedicate this species: 



30. S. flssuni, n. sp. S. minus, quinta parte latins quam longum (proc. incl.); semicellulis 

 cuneatis, ventre inflatis, in 3 angulos superiores bifidos tissis; apice modice convexis; 

 angulis in cornua brevia dua produetis, apicibus 2 — 3-fidis; membrana glabra; sinu 

 brevissimo, rotundato. A vertice visum triangulare, lateribus leniter convexis, angulis 

 sub-acute bitidis. 



Long. 13— U), lat. 17—23, lat. isth. 5—7, long. proc. circ. 5 ju. T. XIV, f. 24 

 (after Wallich Mscr. No. 223). 



Elephant Tank, Kaneegunge, Nov. 1855, G. C. W. 



31. S. quadricornutum, Bov & Bisset (Jap. Desm. p. 240, t, 268, f. 4). Forma. Cel- 

 lulis plus minus depressis; minus gracile quam f. typica. Zygospora giobosa, aculeia 

 longis acutis angustis armata; apud marginem circ. i) visis. 



Long. 24—28, lat, 27—31, lat, isth. 9—10, long. proc. 5—6 ,". T. XIV, f. 2, 

 also Wallich Mscr. No. 221. 



f. 2 c. Zygospore (after Wallich 1. c), Diam. s. acul. 31: long. acul. ( .» — 10 /u. 



S. gemelliparo Nordst. (Desm. Bras. p. 230, t. IV, f. 54) proximum, sed in scia- 

 graphia generali semicellularuni differt. F. Wallichiana sistit. 



f. typica (K. and B., 1. c): 



