46 W. B. TUKNER, FKESU-WATER ALG.E OF KAST INDIA. 



lig. 8 is all after Wallich). The Zygospore has a diameter of 15 — 18 /u. The length 

 of thc isthmal portion of the frond is 2.5 — 3.8 ju. 

 5. S. Muiigulporeauam, n. sp. S. minutum; ferc tam longum quam latum, depresso-ovale; 

 sinu profundo, interne aequali, parumque aperto, externe valde ampliato; semicellulae 

 ovatie, lateribus acuta?, dorso depressae; membrana glabra; isthmo eurto sed distincto 

 inter semicellulas. A vertice visum ellipticum, apiee acutum; a latere clepsydriforme, 

 modice constrietum. 



Long. 8—9, lat. 9, lat. isth. 1.7—2; long. isth. 0.8—1.4; crass. 3.5 fi. T. XVIII, f. 14. 



Certain eorrespondence I have lately had with Algologists induces me to state 

 that I eonsider that when the sinus of a plant is linear the length of isthinus is prac- 

 tically nil, but when in this genus I refer to species possessing isthmi my remark teuds 

 to show that between the semicells there is a distinet and more or less elongated (thougb 

 laterally constricted) 'neck 5 . — It may surely be granted that an isthinus may possess 

 length as well as breadth! 

 0. S. rectuin, n. sp. S. mediocre, fere tertia parte latius quam longum; quadraticum; 

 semicellulae depresso elliptica;, dorso plana.', lateribus rotundatae; membrana laevi; sinu 

 amplo, aperto, sub-aequali, interne rotundato. S. isthmo parum longo, distincto. A 

 vertice visum compresso-ellipticurn; a latere angusto-clepsydriforme, medio modice con- 

 strietum. 



Long. 14—16, lat. 22, lat isth. 6—7, crass. 7—8 [*. T. XVIII, f. 20. 



The isthmus is rather long (3.5 — 4 /u) for the size of the frond. 



7. S. reniforme, n. sp. S. magnum, circ. quarta parte latius quam longum, ovale, valde 

 eonstrictum; semicelluhe reniformes, dorso supplano-convexse, basi paullo dejectte, la- 

 teribus rotundataa; membrana glabra; sinu angusto, extrorsum paullulum contracto- 

 A vertice visum compresso-ovale. Habitu fere cum Cosmario phaseolo Bréb. com- 

 parandum. 



Long. 23—25, lat, 30—32, lat, constr. 5—7, crass. 13 ,u. T, XIX, f. 6. 

 In this species there is an Isthmus, but it is only about 2.5 /n long. 



8. S. lamelliferum, (Corda) Nob. (Sphcerozosma lamelliferum Cokda, Micr. Obs. in Alm. 

 Carlsb. p. 206, t, IV, f. 29, 1840; Archer in Prit, Inf. p. 724, 1861; Kalfs Br. Desm. 

 p. 208; Wille Norges Fersk-alg. p. 58, t, II, f. 40? 1880) var. attenuatiiin, n. v. 



Semicellulae late ellipticae, non reniformes ut in f. typica, lateribus acuto-rotun- 

 datae, apud marginem lateralcm macula unica instructse, dorso leniter convexae, apicc 

 in processu brevi truncato (låtit, fere duplo longit.) producta; membrana glabra; sinu 

 profundo amplo fere aequali interne rotundato. A vertice visum compresso-ellipticurn; 

 »lamella» tenui-elliptica. 



Long. 12 — 14, lat. 19—33, lat. constr. 5 — 6, crass. 7 — 8 fi. 



T. XXI, f. 2x700, after Wallich Mscr. No. 53. 



This seems to be very near to Corda's species, especially as Wallich remarks 

 of the lamella, »a distinet narrow band, thc half of which is always observable on each 

 separated joint (frond)». Archer, 1. c. says »connecting process 'flattened', colourless N 

 — this is exactly after Corda, »membre de réunion feuilleté, blanc>\ so that the pro- 

 trusion at the apices, as shewn by Wallich, is hyaline. The only difference between 



