HOLOTRICHA 535 



except a zone of longer cilia at anterior end; cytostome near 

 median line at the end of the peristome; cytopharynx short; a 

 peculiar 'stripe band' located on dorsal surface has usually its 

 origin in the peristomal groove, after taking an anterior course 

 for a short distance, curves back and runs down posteriorly 

 near right edge and terminates about 1/3 the body length from 

 posterior end; macronucleus rounded; a micronucleus ; contractile 

 vacuole terminal; free-living or endozoic. 



P. nasuta S. (Fig. 244, a). Ovoid; tapering anteriorly; peristome 

 at right angles or sUghtly oblique to the edge; trichocysts at right 

 angles to body surface; macronucleus round to irregular in shape; 

 body about 100m (80-180^) long; sapropelic in brackish water. 

 Lynch (1930) observed this cihate in salt water cultures in Cali- 

 fornia and found it to be 70-1 14^ by 31-56^ by 22-37m. 



P. minuta Powers (Fig. 244, 6). 50-75/x by 36-46^; in intestine 

 of Strongylocentrotus droehachiensis ; the Bay of Fundy. 



Genus Lechriopyla Lynch. Similar to Plagiopyla; but with a 

 large internal organella, furcula, embracing the vestibule from 

 right, and a large crescentic motorium at left end of peristome; 

 in the intestine of sea-urchins. 



L. mystax L. (Fig. 244, c). 113-174/x long; in gut of Strongylo- 

 centrotus purpuratus and S. franciscanus; California. 



Genus Sonderia Kahl. Similar to Plagiopyla in general appear- 

 ance; ellipsoid; flattened; peristome small and varied; body 

 covered by 2-4^ thick gelatinous envelope which regulates os- 

 mosis, since no contractile vacuole occurs (Kahl) ; with or without 

 a striped band; trichocysts slanting posteriorly; in salt or brackish 

 water. Kirby (1934) showed that several species of the genus are 

 common in the pools and ditches in salt marshes of California, 

 salinities of which range 3.5-10 per cent or even up to 15-20 

 per cent. 



S. pharyngea Kirby (Fig. 244, d). Ovoid to ellipsoid; flattened; 

 84-1 lOju by 48-65^; gelatinous layer about 2/i thick, with bac- 

 teria; about 60 longitudinal ciliary rows, each with 2 borders; 

 peristome about 35ai long, at anterior end, obUque; with closely 

 set cilia from the opposite inner surfaces ; cytopharynx conspicu- 

 ous; spherical macronucleus anterior, with a micronucleus; 

 trichocysts (7-9iu long) distributed sparsely and unevenly, oblique 

 to body surface; a group of bristle-like cilia at posterior end; often 

 brightly colored because of food material; in salt marsh, Cali- 

 fornia. 



