Chapter 39 

 Order 2 Spirotricha BUtschli (continued) 



Suborder 2 Oligotricha Butschli 



THE 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. 653) 



With lorica or test Family 3 Tintinnidae (p. 654) 



Parasitic 



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



other cilia Family 4 Ophryoscolecidae (p. 654) 



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



of body, directed posteriorly and nonretractile 



P'amily 5 Cycloposthiidae (p. 659) 



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 micro nucleus; contractile vacuole left of cyto- 

 stome; fresh water. A few species. 



H. grandinella (Miiller) (Fig. 307, a). About 7 bristle-bearing 

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

 (1932) distinguishes 2 varieties: var. cirrifcra (Fig. 307, h), 25-50^ 

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

 (Fig. 307, c), 40-50/1 long, with bristles and large zcochlorellae; 

 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; macro nucleus oval or band-form; a 

 micro nucleus ; a contractile vacuole; salt or fresh water. Numerous 

 species. 



*S. calkinsi Faur^-Fremiet (Fig.307,c?). 35-60/x long; brackish and 

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



652 



