no 



THE INVERTEBRATA 



Spirostomum (Fig. 89 B). Rod-shaped; with the peristome as a 

 long groove; meganucleus beaded; several micronuclei. In fresh 

 waters and marine. 



Stentor (Fig. 89 C). Long and funnel-shaped ; attached by the base, 

 but often frees itself to swim ; meganucleus beaded ; several micro- 

 nuclei. The animal is very highly contractile. In fresh waters. 



M. 



,rods 



mi.-Wti^'r-ri-; 



-meg. 



■vac! 



c.vac. 



c.vac.' 



cvac? 



Fig. 89. Ciliata. After various authors. A, Prorodon teres, x 500. B, Spiro- 

 stomum ambiguum, x 150. C, Stentor coeruleus, x 50, ad.zv. adoral wreath; 

 c.vac. contractile vacuole; c.vac' accessory vacuole; c.vac." accessory canal; 

 f.vac. food vacuole ; ecp. ectoplasm ; M. mouth ; meg. meganucleus ; mi. micro- 

 nucleus ; per. peristome ; rods in protoplasm around gullet. 



Suborder OLIGOTRICHA 



Heterotricha of shortened form; with the body cilia reduced to a few 

 rows or absent. 



This suborder contains two tribes of very different habits, the 

 pelagic Tintinnina, and the Entodiniomorpha, forms of bizarre shape 

 parasitic in the alimentary canal of mammals, chiefly in the stomach 

 of ruminants. Both suborders have an anterior peristome with very 

 strong membranellae, and are naked on the rest of the body, save 

 sometimes for a few cilia or patches of cirri. 



Tintinntdium (Fig. SyC). (Tintinnina.) Cup-shaped ; anchored by 

 an aboral process into a chitinoid case. In fresh waters and marine. 



