HOLOTRICHA 



533 



D. dentata F. (Fig. 243, g). With a small process near cyto- 

 stome; 2 rows of ciliary furrows on both oral and aboral surfaces; 

 cilia on both ends of oral surface; 40-65m long; in fresh water. 



Fig. 243. a, b, Maryna socialis (a, X40; b, Xl60) (Gruber); c, Myc- 

 terothrix erlangeri, X310 (Kahl); d, Trichopelma sphagnetorum, X570 

 (Kahl); e, f, Pseudomicrothorax agilis (e, X340; f, X670) (Kahl); 

 g, Drepanomonas dentata, X540 (Penard); h, Microthorax simulans, 

 X620 (Kahl); i, Trirmjema compressum, X410 (Lackey); j, Spirozona 

 caudata, X370 (Kahl); k, Trichospira inversa, X360 (Kahl). 



Genus Microthorax Engelmann (Kreyella Kahl). Small, flat- 

 tened; with dehcate keeled armor which is more or less pointed 

 anteriorly and rounded posteriorly; ventral armor with 3 ciliary 

 rows; oral depression posterior-ventral, with a stiff ectoplasmic 

 lip on right side, below which there is a small membrane, and 



