36 



ZOOLOGY. 



cavated a mouth and a throat leading to a so-called stomach 

 or digestive cavity. Two hollows in the body form the con- 

 tractile vesicles, and a 

 central mass constitutes 

 the reproductive organ. 

 Prolongations of the body- 

 mass form the cilia, which 

 characterize the Infusoria 

 and give the name to the 

 present order, Ciliata. 

 Paramecium has an elon- 

 gated, oval body "with 

 one end (H ) flattened out 

 broader than the other, 

 and twisted about one- 

 third way round, so that 

 the flattened part resem- 

 bles a very long figure 8." 

 In this form, as well as in 

 Stentor (Fig. 25), as Clark 

 remarks, " we have the 

 mouth at the bottom of a 

 broad notch or incurva- 

 tion, and the contractile 

 vesicle on the opposite 

 side, next the convex 



Fig. 25. Stentor polymorphus, magnified 130 back, whilst the general 

 diameters, expanded and bent slightly over to- pflv :j._. nf fho hnrlv lios ho 

 ward the observer; the mouth TO, next the eye, CdVlty Ol LlltJ >OUy 11 

 and the dorsal edge in the distance, d. poste- j. fhp> fwn " Tho 



rior end; sh, the tube enclosing d ; c, the cili- een tliese two - 



hi the^xtreme arrows i n the figUl'6 rcpre- 



af cp 6 sen ^ ^ ne courso ^ t ne par- 



in the distance; rH, the circular and'radiating tides of indiffO Avitll which 

 branches of what, by Clark, was supposed to be " 



a rndlmentary nervous system: n, n*. the re- Clark led lllS Specimens, 

 productive system, extending from the right , .. . 



side, at w, posteriorly, but toward the eye at n'. as they are whirled 

 After Clark. n i_ .* i -i 



along, by the large vibrat- 

 ing cilia (v) of the edge of the disk, against the vestibule of 

 the mouth." During the circuit the food is digested, a 

 mass of rejectamenta is formed near the protuberance, a, 

 which has appeared a short time before. This finally 



