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 

 F1-. i&.-stentor poiymoiyhu^^^ ia> back, whilst the general 



diameters, expanded and bent slightly over to- y ;j- v o f 4-] ie body lies IjC- 

 wunl the observer; the mouth wi, next the eye, CdVlty < uy 



and the dorsal edge in the distance, d poste- f weell tllCSC two. ' The 

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

 ated border of the disk (s); v, the larger rigid arro \ vs m the figure repre- 

 ciliu- CD, the contractile vesicle in the extreme . , i 



dietance,seen through the whole thickness of the se nt the COUl'SC OI the par- 

 body; CT 1 , CT Z , the posterior prolongation of co, , . , 

 in the distance; >, r l , the circular and radiating tlCieS Ot lllCUgO AVltll WlllC'll 

 branches of what, by Clark, waa supposed to be , . 

 a rudimentary nervous system; it, //'. the re- Clark led. hlS Specimens, 

 productive system, extending from the right l( , Avhirlnd 

 side, at n, posteriorly, but toward the eye at /t 1 . Ub tliey dl 



-After Clark. 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 



