— 22 — 



1 have seen but few chains of this large species, which has some 

 relations to C. eonstrictum Gran (the two chromatophores) and others to 

 C. teres CI. and C. Weissflogii Schütt (the form of the valves and the 

 awns). 



10 (rr). 



Obs. The undulations of the awns are not well drawn in the 

 figure. 



60. C. tetrastichon Gleve, Phytoplankton p. 22,- Pl. I, f. 7; Schröder, 

 I. e. p. 30; Ostenfeld & Schmidt, PL f. the Red Sea, etc. p. 256 ; Gleve, 

 PL f. the Indian Ocean and the Malay Archipelago p. 19. 



2 (rr). 



Area: Tropical Atlantic Ocean, Naples, Red Sea, Malay Archipelago. 



61. C. Vanheurckii Gran, Norske Nordhavs Expedition, Protophyta, 

 p. 18; C. Ralfsii Van Heurck Synopsis, PL 82 bis, f. 3, non Gleve. 



I have found a form which I identify with the C. Vanheurckii, 

 described by Gran in his excellent paper on the Norwegian species of 

 Chaetoceras. My figures of a part of a chain and of the spores agree 



Fig. 18. Chaetoceras Vanheurckii Gran. Chain endospores in front view 

 in front view, cell in side view ( 4 p). ( 2 , 5 )- 



rather well with the description by Gran; the chains are straight, fora- 

 mina lanceolate to narrow-elliptic, hoop about a third part of the cell 

 with constricted sutures; chromatophore one; awns straight, seen from the 

 valve diverging at a right angle ; spores about in the middle of the cells, 

 primary valve arcuate with numerous spines, secundary valve humped 

 with longer spines on the humpe; further both valves possess along the 

 margins a wreath of parallel, straight apiculi. 



10 (r). 



Area: Yeddo Ray. 



