BIIIAXG TILL K. SV. VE I'. AKAD. IIANDL. BAND. 1. N:0 11. 11 



87. Rhizosolenia robusta Norman (in Pritcli. Infus. 1861 

 pa<i;. 8()(). Pl. \'III i\'^. 42) somewhat rare. 



This large species, certainly the largest of all diatoms, has 

 been found before in the North Sea and near Avistralia. 



The genus Rhizosolenia, puzzling as its forms may be 

 found on a first inspcction, seems to me to be very closely 

 related to the Hemiaulida^ being to that family in about the 

 same relation as the Isthmia to the Biddulphiea?. The annuli 

 of the connectlng membrane are perhaps nothing hut the joints, 

 by which the connecting membrane breaks up, Avhen new fru- 

 stules are growing out after the division, almost as the annuli 

 ncar the ends of the cells of several species of Oedogonium. 



38. Rhizosolenia imbricata Beightw. (i\l. J. Vol. VI pag. 

 04 Pl. V hg. G) not uncommon. 



This beautiful species is easily distinguished from all the 

 other by its coarse granides arranged in curved llnes. 



39. Rhizosolenia Calcar Avis Max Schulze (M. J. Vol. 

 VII pag. 19 Pl. II fig. 5 — -10) not imcommon. 



Found before in the North Sea. Colour of dry valve light 

 blue, annuli very distinet. 



40. Rhizosolenia alata Brightw. (M. J. Vol. VI pag. 95. 

 Pl. V fig. 8). 



This species is not rare and attains sometimes a very consi- 

 derble length. Colour of the dry valve purplish. Found before 

 in the Nortliern Atlantic and according to Giamow near ihe Ni- 

 cobarian Islands. 



41. Rhizosolenia styliformis Brightw. (1. c. pag. 95 Pl. V 

 Hg. '")) very rare; ibund before in the northern Atlantic, in the 

 North Sea, near Callao and Nicobarian Islands (Grunow). 



42. Rhizosolenia setigera Brightw. (1. c. pag. 9 Pl. V 

 Hg. 7). Somewhat rare; found before near the Nicobarian Is- 

 lands (Grunow). 



43. Campylodiscus Brightwellii Geun. (A'crh. 1862 pag. 445 

 Pl. IX fig. 4. C. str latas Btw. iM. J. VII pag. 179. Pl. IX 

 fig. 4) extrem ely rare. 



44. Novilla fastuosa (Sm.) Cl. -{Surirellaf. Sm. Syn. Vol. I 

 pag. 32 Pl. IX iig. •)()) very rare. 



