4 o6 



THE INFUSORIA 



large elongated contractile vacuole. Numerous micronuclei. 3 mm. in 

 length when fully extended. Marine and fresh- 

 water. (Figs. 57, 58.) 



Family BURSARINA, Biitschli. Thylakidium, 

 Schew. With a long ventral peristome. The 

 medulla contains numerous zoochlorellae. Fresh- 

 water in Australia. Balantidium, Clap, and L. 

 A large peristome and well-marked anal aperture. 

 0'5. Very common in the rectum of Batrachia, 

 occasionally found in the large intestine of man 

 and in the coelom of Annelida. Balantidiopsis, 

 Biitschli. A smaller peristome than in Balanti- 

 dium. 0*15. Intestine of Rana esculenta. 

 Club-shaped in form. The 



Fio. 56. 



Nyctotherus cordiformis, 



Ehrb., as seen from the right Condvlostoma. Dui. 

 side, a, ineganucleus ; b, a 



OH.4C. (by MHXpUAU^AVlM , I/, * 1 j. 1 1 P 



water vacuole ; c, contractile right border Ot 



vacuole ; d, anus ; e, band of 

 long cilia ; /, microimcleus ; 



lin d n l a tino- 

 l LUa n g 



the peristome bears a large 

 0*5. Marine and freshwater. 



, 

 mouth ; Ji, pharynx ; i, Bursaria, Clap, and L. The peristome is an 



Swabout^is mm?in length? enormous excavation on the anterior and ventral 

 face of the body. Meganucleus strap - shaped. 



Micronuclei 16 or more. 1-5. Very common in some freshwater ponds. 

 (Figs. 58 and 59.) Bursaridium, Lauterb. 



Family STENTORINA, Stein. Climacostomum, Stein. The form of the 



body is oval and shows little con- 

 tractility. The peristome is large and 

 oblique. It is in many ways intermediate 



Spirostomum ambiguum, Ehrb. On 

 the right Hide of the peristome the long 

 cilia of the adoral zone, a, a, nionili- 

 form ineganucleus ; b points to the 

 enlarged part of the contractile vacuole; 

 in front of this letter it is drawn out 

 into a narrow tube, x 100. 



O " 



Fio. 58. 



Spirally contracted condition of 

 Spirostomum ambigmim, Ehrb. ci.c.r, 

 the duct of the contractile vacuole; 

 0.2, adoral zone ; o, mouth. (P'rom 

 Biitschli, after Lieberkuhn.) x 120. 



between Balantidium and the STENTORINA. 0'36. Freshwater. Stentar, 

 Oken. Elongated trumpet -shaped form, with a well -developed adoral 

 zone at the broadest end. A long moniliform meganucleus and several 



