106 INTRODUCTION TO POLYZOA. 



Sub-order 2 Cyclostomata. 



Zooecia tubula, with a plain terminal orifice without operculum. 

 Without movable appendages. The ovicells are modified 

 zooecia. 



TRIBE A. AETICULATA. TRIBE B. INAKTICTJLATA. 

 1 Family. 4 Families. 



Sub-order 3 Ctenostomata. 



When the tentacle-sheath is retracted, the orifice of the 

 zooecium is closed by a folded membrane as by an operculum. 

 Zoarium never calcareous. Ovicells and appendages absent. 



TRIBE A. HALCYONELLEA. 3 Families. 

 TRIBE B. STOLONIFERA. 7 Families. 



Order //. PHYLACTOL^EMATA. 



Fresh-water Polyzoa with horse-shoe-shaped 

 lophophore and epistome. 



FAMILY 1 CKISTATELLID^E. 

 FAMILY 2~PLUMATELLID^B. 



CLASS II ENDOPEOCTA. 

 Anus within the tentacular circlet. 



Arranged by & & After SEDGWICK. 



I 



