5 I 8 POLYZOA 



2. The Cheilostomata consist of (A) the Cellulakina, including 

 the flexible, erect forms, such as Bugula (Fig. 233) and Scrupo- 

 cellaria (Fig. 254); (B) the Flustkina, to which belong Flustra 

 (Fig. 232), Membranipora (Fig. 256, A, B), Micropora (Fig. 

 256, C), and other forms in which the front wall of the zooecium 

 is either membranous, or depressed and marked off by a ridge- 

 like margin ; (C) the Escharina, including the great majority of 

 forms, in which no part of the front wall remains membranous, 

 the wall of the zooecium being wholly calcified. 



3. The Ctenostomata comprise (A) the Alcyonellea or en- 

 crusting forms ; and (B) the Vesiculapjna or branching forms. 

 The zooecia in the latter subdivision (Fig. 238) are given off from 

 a tubular stem or stolon, which is usually erect and branching. 



We thus have the following arrangement of recent forms. 

 The genera mentioned are for the most part those which have 

 already been alluded to in the preceding account : 



Sub-class I. Entoprocta. 



Loxosoma, Pedicellina, Umatella. 



Sub-class II. Ectoprocta. 

 Order 1. Gymnolaemata. 



Sub-order 1. Cyclostomata. 



A. Articulata. Crista. 



B. Inarticulata, Hornera, Idmonea, Tubulipora, Stomato- 



pora, Diastopora, Entalophora, Lichenopora. 

 Sub-order 2. Cheilostomata. 



A. Cellulariua. Aetea, Eucratea, 1 Catenicella, Cellularia, 



Gemellaria, Menipea, Sci-upocellaria, Caberea, Notamia 

 ( = Epistomia), Bicellaria, Bugula, Beania. 



B. Flustrina. Gellaria, Flustra, Memhranipora, Electra, 



Lunulites, Membraniporella, Cribrilina, Micropora, 

 Selenaria. 



C. Escharina. Retepora, Microporella, Lepralia, Porella, 



Smittia, Mucronella, Schizoporella, Schizotheca, Masti- 

 cjophora, Porina, Gellepora. 

 Sub-order 3. Ctenostomata. 



A. Alcyonellea. Alcyonidium, Flustrella. 



B. Vesicularina. Vesicularia, Amathia, Boiuerbankia, 



Farrella, Hypophorella, Triticella, Mimosella, Victor- 

 ella, Paludicella. 

 Order 2. Phylactolaemata. 



Fredericella, Plumatella (including Alcyonella), Lophopus, Crista- 

 tella, Pectinatella. 



1 Aetea, Eucratea, and certain other forms were separated off by Mr. Busk as a 

 distinct division, the Stolonata. 



