SPIROTRICHA, HYPOTRICHA 



837 



U. pohjmicronucleata Merriman. Elliptical with broadly rounded 

 ends; flexible; 225m by 65m; opaque, green or brown because of the 

 ingested diatoms; 3 large and 10 small frontals; four ventral rows of 

 cirri; marginals; macronucleus in two parts; three to 11 micronuclei 

 (Merriman, 1937). 



U. coei Turner. Elliptical, with a more pointed posterior end; 200 m 

 by 50m; four rows of ventral cirri, the right row being the longest; 

 five frontals; macronucleus in two masses; four micronuclei (Turner, 

 1939). 



Genus Kerona Ehrenberg. Reniform; no caudals; 6 oblique rows 

 of ventral cirri; commensal. One species. 



Fig. 356. a, Urostyla caudata, X90 (Stokes); b, Kerona polyporum, 

 X200 (Stein); c, Keronopsis rubra, X270 (Entz); d, Epiclintes pluvialis, 

 XlOO (Smith); e, Holosticha vernalis, X220 (Stokes); f, H. hymenophora, 

 XlSO (Stokes); g, Paraholosticha herbicola, X200 (Kahl); h, Trichotaxis 

 stagnatilis, X190 (Stokes); i, Balladyna elongata, X800 (Roux); j, Pleu- 

 rotricha lanceolata, X250 (Stein); k, Gastrostyla muscorum, X200 (Kahl). 



