INFUSOBIA 



59 



1. BURSARIA 0. F. Miiller. Body large, purse-shaped, obliquely 

 truncate in front; nucleus long, ribbon-like: 1 species; in fresh water. 



B. truncatella Mill. (Fig. 100). Length 1 mm. 

 and more: often between fallen leaves in the 

 water. 



2. BALANTIDITJM Stein. Body spindle-shaped, 

 with the oral groove at the apex : 4 species, para- 

 sitic in mammals, amphibians, and worms. 



B. coli St. (Fig. 101). Length .12 mm.: in 

 the large intestine of the pig and man, causing 

 diarrho3a. 



B. entozoon (Ehrenberg). Length .2 mm.: 

 in the large intestine of frogs, toads, and 

 salamanders. 



3. CONDYLOSTOMA Dujardin. Body rounded or cylindrical, tapering 

 anteriorly with obliquely truncate forward end; nucleus bead-like: 2 

 species, in fresh and salt water. 



C. patens (0. F. Miiller) (Fig. 102). Length .4 mm.; width .10 

 mm.: fresh and salt water. 



Fig. 100 



Bursaria truncatella 

 (Conn). 



Fig. 101 



Fig. 102 



Fig. 103 



Fig. 101 Balantidium coli (Doflein). Fig. 102 Condylostoma patens (Calkins). 

 Fig. 103 Stentor coeruleus (Doflein). 



FAMILY 3. STENTOBIDAE. 



Body the shape of an elongated funnel and very contractile, the 

 small end of which can be attached; large end truncate, the adoral zone 

 passing around the edge; nucleus usually beaded: 2 genera; in fresh 

 water. 



STENTOR* Oken. Fixed or free-swimming; when swimming body 

 is contracted and ovate: 8 species; in fresh water. 



S. cceruleus Ehrenberg (Fig. 103). Body blue; length .25 mm. 



* See "Selection of Food in Stentor coeruleus (Ehr.)," by A. A. Schaeffer, Jour. 

 Exp. Zool., Vol. 8, p. 839, 1910. 



