Chapter 38 

 Order 2 Spirotricha Biitschli (continued) 



Suborder 2 Oligotricha Biitschli 



THE cilia are greatly reduced in number in the Ohgotricha and 

 the adoral zone encloses a non-ciliated spiral peristomal field. 



Free-living 



Oral portion of peristome lies free on ventral surface 



Family 1 Halteriidae 



Adoral zone encloses frontal peristomal field in a closed spiral 



Without lorica Family 2 Strobilidiidae (p. 589) 



With lorica or test Family 3 Tintinnidiidae (p. 589) 



Parasitic 



Adoral and dorsal zones, both directed anteriorly and retractile; no 



other cilia Family 4 Ophryoscolecidae (p. 590) 



In addition to adoral and dorsal zones, groups of cirri in posterior 



half of body, directed posteriorly and nonretractile 



Family 5 Cycloposthiidae (p. 596) 



Family 1 Halteriidae Claparede et Lachmann 



Genus Halteria Dujardin. Spherical or broadly fusiform; an- 

 terior border bears conspicuous adoral zone; oral part of peri- 

 stome with a small membrane on right edge and cirri on left ; with 

 an equatorial zone of small oblique grooves, each bearing 3 long 

 cirri or bristles; macronucleus oval; a micronucleus; contractile 

 vacuole left of cytostome ; fresh water. A few^ species. 



H. grandinella (Miiller) (Fig. 266, a). About 7 bristle-bearing 

 grooves; 15 frontal and 7 adoral membranellae ; 20-40^ long. 

 Kahl (1932) distinguishes 2 varieties: var. cirrifera (Fig. 266, h), 

 25-50^ long, with huge cirri instead of fine body cirri; and var. 

 chlorelligera (Fig. 266, c), 40-50^ long, with bristles and large 

 zoochlorellae ; fresh water. 



Genus Strombidium Claparede et Lachmann. Ovoid to spher- 

 ical; adoral zone very conspicuous (2-4 conspicuous sickle-form 

 frontal membranellae and adoral membranellae extend down 

 cytopharynx, the first section surrounding an apical process) ; no 

 body bristles or cirri; trichocysts; macronucleus oval or band- 

 form ; a micronucleus ; a contractile vacuole ; salt or fresh water. 

 Numerous species. 



587 



