112 W. R. TIRXEE, ERESH-WATER AXjQM OK KAST INDIA. 



dififérs in the apiees being elevåted not plane, and in the apieal tnbercles, also in the 

 regularly ovate shape of the semieells. The onlv good figure yet published of St. lon- 

 gispinum Bail. seema to be that of Lagerheim (Bidr. Amer. Desfn. Fl. p. 249, t. 

 XXVII, f. 28) from which, both in appearance and diniensions, this Desmid differs 

 eonsiderablv. I would, however, remark that in American planta the semieells are 

 often raore distinctly cuneate, the isthmus being a little narrower, than in the icon of 

 Lagerheim. Vide No. 123, sfeq. 



35. S. papillosum, Kirchner (Alg. Schles. p. 170, 187N; Boldt Sibir. Chloroph. p 114, 

 t. V, f. 23. Forma. 



Long. 46, lat, 51, lat. isth. 20 fi. Wallich Mscr. Xo. 184. 



40, » 40, » » 18—23 fi. T. XIII, f. 18. 

 It is interesting to note yet another Siberian form in India; contrary to the ma- 

 joritv of forms this is larger than that of the eolder elimates. 



3<>. S. cristatumJ (Xäg.) Archer (in Prit. Inf. p. 738; Phycastrum (Pachyactinium) rri- 

 statum Näg. Einz. Alg. p. 127, t, Mil c. f. 1, 1849; Staurastrum niti<luin Archer 

 Dub. Nat. Hist. Rev. t. I, f. 3, 4, 1859). Forma: 



Long. 34, lat. 42, lat. isth. 11.5, long. spin. 5—0 ,u. T. XVI, f. 44. 



This plant secms to be near those figured by Xägeli and Archer, and yet to 

 differ from them in its generally granular angles and seattered spines, it is much like 

 one figure I have seen of Stan. oligacanthum Breb. (sp. ined.), but yet is nnlike the 

 ieons of Xordstedt (Desm. Arctoae, t. VIII, f. 39), in which the spines are blunt. I 

 . fcar that the identity of Brebissons species will not be settled until someone per- 

 chance is permitted to inspee.t the original specimens of the author. 



Northern India. 



37. S. denticnlatnm (Näg.) Archer (in Prit. Inf. ]>. 73S, 1801; Phycastrjiim (Pachyactinivm) 

 denticulatum Näg. Einz. Alg. p. 128, t. XIII (\ f. 3, 1849). Forma? 



Lat, 41, long. spin. 3 /u. A lin \isa non observata. T. X\T, f. 50. 

 Northern India, J. S. 



This seems near to Xäoelis form, but is hardly the same — as he represents 

 the sides in vert. v. as dentienlate, and in f. v. the angles perfeetly striolate. 



38. S. echinatum Breb. (in Kales Br. Desm. p. 215, t. XXXV, f. 24, 1848; Liste, p. 

 141, 1850). 



Long. 44, lat. 40 (sp. inel.), lat. isth. 11, long. spin. 7 — 8 fl. T. XVI, f. 4s- 

 Northern India, J. 8.; East India, from Utrieularia fascicnlata, (i. x. L. 



39. S. gladiosum? Tcrner (On Desm. p. 938, t, XVI, f. 21, 1XS5). \'. lotmispinuiii. Spi- 

 nn 1 i s valde clongalis, longitudine irregnlaribns. 



Long. 40, lat. 48, lat. isth. 13, long. spin. !» — 17 u. T. XVII, f. 2 (Wallich 

 Mscr. Xo. 180). 



In this var. the semieells are ovato-enneate, not so regularly ovate as in the 

 type, the spines of which are abont — 7 ,u long, whilst in the varietv thev are ninch 

 longer and varv mnch in length. As the long. and lat, (e. sp.) are 52 and 0<>// respec- 

 tively, this may be the S. shgittyferu&n Borg. (Desm. Brak. p. 951), t. \', f. 40)? 



