DINOFLAGELLATA 



31' 



ter, due to the presence of an osmotically active substance with a 

 lower specific gravity than sodium chloride, which appears to be 

 ammonium chloride (Goethard and Heinsius); certain granules are 

 luminescent (Fig. 128); cytoplasm colorless or blue-green; sometimes 

 tinged with yellow coloration in center; swarmers formed by bud- 

 ding, and each possesses one flagellum, annulus, and tentale; widely 

 distributed in salt water; holozoic. One species. 



N. scintillans f Macartney) (N. miliaris S.) (Figs. 127, i,j; 128). 

 Usually 500-IOOOm in diameter, with extremes of 200/u and 3 mm. 

 Gross (1934) observed that complete fusion of two swarmers (isoga- 

 metes) results in cyst formation from which trophozoites develop. 

 Acid content of the body fluid is said to be about pH 3. Nuclear di- 



Fig. 128. Noctiluca scintillans, as seen under darkfield microscope 

 (Pratje). a, an active individual; b, a so-called "resting stage," with fat 

 droplets in the central cytoplasm, prior to either division or swarmer 

 formation; c, d, appearance of luminescent individuals (F, fat-droplets; 

 K, nucleus; P, peristome; T, tentacle; V, food body; Z, central proto- 

 plasm). 



