T 



Chapter 39 

 Order 2 Spirotricha Biitschli (continued) 



Suborder 2 Oligotricha Biitschli 



HE cilia are greatly reduced in number in the Oligotricha 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 



Without lorica Family 2 Strobilidiidae (p. 815) 



With lorica or test'. Family 3 Tintinnidae (p. 816) 



Parasitic 



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



other cilia Family 4 Ophryoscolecidae (p. 816) 



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



of body, directed posteriorly and nonretractile 



Family 5 Cycloposthiidae (p. 823) 



Family 1 Halteriidae Claparede and Lachmann 



Genus Halteria Dujardin. Spherical or broadly fusiform; anterior 

 border bears conspicuous adoral zone; oral part of peristome 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; 

 macro nucleus oval; a micronucleus; contractile vacuole left of cyto- 

 stome; fresh water. Several species (Szabo, 1935). 



H. grandinella (Miiller) (Fig. 347, a). About 7 bristle-bearing 

 grooves; 15 frontal and 7 adoral membranellae; 20-40/x long. Kahl 

 (1932) distinguishes 2 varieties: var. cirrifera (Fig. 347, b), 25-50ju 

 long, with huge cirri instead of fine body cirri; and var. chlorelligera 

 (Fig. 347, c), 40-50/x long, with bristles and large zoochlorellae; 

 fresh water. 



Genus Strombidium Claparede and Lachmann. Ovoid to spher- 

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

 frontal membranellae and adoral membranellae extend down cyto- 

 pharynx, 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. 



S. calkinsi Faur6-Fremiet (Fig. 347, d). 35-60/z long; brackish and 

 salt water; Calkins (1902) first observed it at Woods Hole. 



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