bo 
Lo 
240 
I have seen but few chains of this large species, which has some 
relations to C. constrictum Gran (the two chromatophores) and others to 
C. teres Cl. and C. Weissflogii Schiitt (the form of the valves and the 
awns). 
10 (rr). 
Obs. The undulations of the awns are not well drawn in the 
figure. 
60. ¢. tetrastichon Cleve, Phytoplankton p. 22, Pl. I, f. 7; Schréder, 
l.c. p. 30; Ostenfeld & Schmidt, Pl. f. the Red Sea, ete. p. 256; Cleve, 
Pl. f. the Indian Ocean and the Malay Archipelago p. 19. 
2 (rr). 
Area: Tropical Atlantic Ocean, Naples, Red Sea, Malay Archipelago. 
61. (. Vanheurckii Gran, Norske Nordhavs Expedition, Protophyta, 
p. 18; C. Ralfsii Van Heurck Synopsis, Pl. 82 bis, f.3, non Cleve. 
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. 19. Chaetoceras Van- 
heurckit Gran. Chain with 
Fig. 18. Chaetoceras Vanheurckit Gran. Chain  endospores in front view 
in front view, cell in side view (425). (235). 
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 (1). 
Area: Yeddo Bay. 
