CHAPTEE XVI. 



BRYOZOA ECTOPROCTA. 



Colonial Bryozoa with the anus outside the lophophore, with a 

 well-developed introvert and a spacious coelom. 



Systematic : — 



A. PHYLACTOLAEMATA. Fresh-water forms, with horse- 

 shoe-shaped lophophore prolonged into two arms; with epistome 

 overhanging the oral aperture (Oristatella, Plumatella, Pectinatella, 

 Fredericella). 



B. GYMNOLAEMATA. Mostly marine; with circular lopho- 

 phore; without epistome. 



I. Cyclostomata. Apertures of the zooecia terminal, circular 

 and devoid of closing apparatus; without appendages (Crista, 

 Diastopora, Horner a, Tubulipora, Frondipora). 



II. Ctenostomata. Apertures of the zooecia terminal, closable 

 by means of tooth-like or seta-like projections of the tentacle-sheath. 



1. Haley onellea (Alcyonidium, PJierusa, Flustrella). 



2. Stolonifera (Vesicularia, Atnathia, Boiverbankia, Farella, 

 Hypophorella ; the fresh-water forms Paludicella and Victorella 

 also belong here). 



III. Chilostomata. Apertures of the zooecia not, as a rule, 

 terminal, usually closable by a movable lid. 



1. Stolonata (Aetea, JSucratea). 



2. Radicellata. 



a. Cellularina (Cellularia, Scrupocellaria, Bugula). 



b. Flustrina (Flustra, Membranipora). 



c. Escharina (Retepora, Microporella, Eschar a, Lepra! i a, 



JSchizoporella). 



