E U CILIA TA , HOLO TRICHIDA 



351 



contractile vacuole posterior. Feeding on other ciliates, es- 

 pecially Paramecium. Fresh water. 



Fig. 151 a. Enchelys teres. X 100 (After Stokes). 



b. E.truncata. X 200 (After Stokes). 



c. Lagynus elegans. X 165 (After Engelmann). 



d,e. Spathidium spathula. X200 (After Woodruff and 

 Spencer), e, individual swallowing a Colpidium. 



f-j. Didinium nasutum. X165. f, g, living specimens; h, 

 a stained specimen; i, dividing form, stained; j, an 

 individual swallowing Paramecium caudatum. 



k. Monodinium balhiayiii. X285 (After Butschli). 



1. Mesodinium pulex. X665 (After Calkins). 



m. Dinophrya Heberkiihni. X300 (After Butschli). 



