56 



CLEVE, PLANKTON FROM THE INDIAN OCEAN AND THE MALAY ARCHIPELAGO. 



were found, and it is almost impossible to distinguish C. teres Cl. and C. Weissflogii, 

 when sterile, but the former belongs to arctic currents, for which reason I believe that 

 the specimens from the Malay Archipelago belong to C- Weissjiogii. 



Fragilaria Aurivillii Cl. n. sp. 

 (Pi. vin, fig. 13). 



Frnstules uniting into long bands. Their sagittal axis about 5 — 6 times longer 

 than the pervalval axis. Zone with close, parallel lines. Valve obtuse, with one to three 

 constrictions. No structure could be discovered. Cell-contents with numerons small chro- 

 matophores. Sagittal axis O, os to 0,08 mm.; transverse axis 0,oo6 to 0,oo8 nnn. 



Fragilaria hyalina (Kutz) Grun. 



Fig. 1. 



The diatom, which I consider to be this species, occurred on gelati- 

 nous stalks in Diatoma-Yike chains, fastened on the furca of a copepode 

 {Candace). The chromatophores were in each cellula 4. The f]"ustules 

 did not show any perceptible structure with exception of the zone, which 

 was very closely longitudinally striate (about 20 lines in 0,oi mm.). 



Palmeria Hardmaniana H. L. S 



M. 



This large and beautiful diatom seems to me to be an asymmetrical 

 form of Coscinodiscus nohilis Grun., the structure being identical. The 

 Fig. 1. Fragilaria CJusc. papuanus Castr. seems, to judge from the figure, not to differ from 



hyalina. 450 t. m. ^,_ ^^^^.^.^, 



llM ! 



RMzosolenia cocMea Brun. 



(Pl. VIII, lig. 12). 



The chromatophores are very small and numerous, elongated and grouped in a 

 nuiiil)er of oblique or spirally twisted bands. 



Rhizosolenia pellucida Cl. n. sp. ^ 



(Pl. VIII, fig. 4). . '^. , , 



Frustule cylindrical, hyaline and slightly silicious. Valve very oblique, ends in a 

 short slightly curved spine and has on the shorter end a small fnrrow for the reception 

 of the spine of other frustules. The zone has very delicate fulcral lines, which cross 

 each otlier, thus forming rhombic figures, 2 of which are to be seen on each half of the 

 circumference of the zone. The chromatophores are very small, i'ounded and scattered 

 without order. Pervalval axis 0,2 to 0,3 mm. ; transverse and sagittal axis 0,o36 to 0,04 mm. 



^ Since the above was written, this species has beeu described by OsTENFELD (Vidensk. Meddel. fra deu 

 Naturh. Förening i Kblivn 1901, \\. Kil) as ]'. li/jaliiin, wliirh name has iniority. 



