CONTENTS xi 



Tribe 1 Prostomata 496 



32 Tribe 2 Pleurostomata 517 



Tribe 3 Hypostomata 522 



33 Suborder 3 Trichostomata 531 



34 Suborder 4 Hymenostomata 547 



35 Suborder 5 Thigmotricha 560 



36 Suborder 6 Apostomea 567 



37 Order 2 Spirotricha 573 



Suborder 1 Heterotricha 573 



38 Suborder 2 Oligotricha 587 



39 Suborder 3 Ctenostomata 600 



40 Suborder 4 Hypotricha 603 



41 Order 3 Chonotricha 614 



42 Order 4 Peritricha 616 



43 Class 2 Suctoria 628 



Author and Subject Index 643 



