SPIROTRICHA, HETEROTRICHA 583 



1-2 mm. long; anterior end greatly expanded; the beautiful blue 

 color is due to a pigment, stentorin, lodged in interstriation gran- 

 ules; macronucleus beaded; Burnside (1929) studied its body and 

 nuclear sizes (p. 114). 



S. striatus Barraud-Maskett. Dark bluish green; funnel-shape; 

 peristomal edge irregularly undulating; striation conspicuous; 

 macronucleus beaded; up to 2.2 mm. long. 



S. yolymor-phus (Miiller) (Fig. 264,/). Colorless; with zoochlo- 

 rellae; 1-2 mm. long when extended; macronucleus beaded; an- 

 terior end expanded. 



S. mulleri (Bory) (Fig. 265, g). Colorless; with zoochlorellae; 

 2-3 mm. long; anterior end expanded; posterior portion drawn 

 out into stalk, often housed in a gelatinous tube; on body surface 

 3-4 longer and stiff cilia grouped among cilia; macronucleus 

 moniliform. 



*S. roeseli Ehrenberg (Fig. 264, h). 0.5-1 mm. long; anterior end 

 expanded; body surface with groups of longer ciha; posterior por- 

 tion, drawn out and often housed in a gelatinous tube; macronu- 

 cleus long band-form. 



S. igneus E. (Fig. 264, i). Rose-colored or colorless; 200-400m 

 long; macronucleus oval; ciliation uniform. 



S. niger (Miiller). Yellowish or brown; macronucleus oval; 200- 

 300)u long. 



S. multiformis (Miiller). Dark blue to bluish green; anterior 

 end not expanded; 150-200^ long; macronucleus oval. 



S. amethystinus Leidy (Fig. 264, j). Habitually pyriform (con- 

 tracted); amethyst-blue; with zoochlorellae; 300-600^ long; 

 macronucleus oval. 



S. pyriformis Johnson. When extended 500/u long; anterior end 

 200ju in diameter. 



Genus Fabrea Henneguy. Pyriform; posterior end broadly 

 rounded, anterior end bluntly pointed; peristome extends down 

 from anterior end 2/5 or more the body length, its posterior por- 

 tion closely wound; peculiar black spot beneath membranellae 

 in anterior portion of spiral adoral zone, composed of numerous 

 pigment granules; without contractile vacuole; macronucleus, a 

 sausage-shaped body or in 4 parts ; in salt water. 



F. salina H. (Fig. 265, a, h). 120-220m by 67-125m (Kirby); 

 130-450^ by 70-200m (Henneguy) ; cysts ovoidal, with gelatinous 

 envelope; 89-11 l^i by 72-105^. Ivirby (1934) found the organism 



