INTRODUCTION TO THE PROTOZOA 37 



Family PARAMECIIDAE 



With oral groove extending from the anterior end toward 

 the middle of the body. Somatic ciliation complete and 

 essentially uniform. Adoral ciliature including a dorsal 

 zone of long cilia (quadripartite membrane) and 2 peniculi 

 (dense bands of cilia extending in a shallow spiral toward 

 the cytostome). 



Paramecium 



Family TETRAHYMENIDAE 



Adoral ciliature composed of 3 membranelles lying to the 

 left in the oral pouch; a fourth, paroral membrane extends 

 along its right margin. One or more stomatogenous rows 

 of cilia end at the posterior margin of the oral pouch. 



Tetrahymena 



Subclass SPIROTRICHASINA 



Bases of adoral zone membranelles usually at right or oblique angle to long 

 axis of adoral zone; this series of membranelles extends anteriorly from the 

 left margin of the cytostome; the basal plate of each membranelle contains 

 2, 3 or rarely 4 rows of basal granules. 



Order HETEROTRICHORIDA 



Somatic ciliation usually complete. Peristome usually elongated and 

 fairly narrow, with adoral zone of membranelles along left wall. An 

 undulating membrane often extends for some distance along right mar- 

 gin of peristome. 



Family PLAGIOTOMIDAE 



Body densely ciliated. Adoral zone of membranelles well 

 defined. Undulating membrane at right margin of peri- 

 stome. 



Nyctotherus 



Order ENTODINIORIDA 



Ciliation may be limited to the adoral zone; there may be 1 or more 

 additional bands or groups of membranelles. Skeletal plates usually 

 present. 



