210 NATURAL HISTORY OP 



ductive capacity of tlie colony in case of injury, or 

 upon tlie disintegration of the cells in which they are 

 contained. 



In consequence of the respiratory functions of the 

 tentacles, and for other reasons, most naturalists, 

 especially English ones, consider the Polyzoa as be- 

 longing to the sub-kingdom Mollusca, or to a branch 

 of that sub-kingdom called the Molluscoida.* Conti- 

 nental zoologists apply the term " Bryozoa " to these 

 animals. This term was first used by Ehrenberg in 

 1831, but as the term '^Polyzoa'' had been used in 

 Thomson's researches in 1880, the latter clearly has 

 priority, and is universally used in England. 



CLASSIFICATION OF THE BRITISH 

 POLYZOA. 



The PoLYzoA are a class of the division Molluscoida 

 of the sub-kingdom Mollusca.* They are classified as 

 follows : — 



Sub-class I. Holobranchia. (Tentacles in an un- 

 broken series.) 



Group a. Ectoprocta. (Anal orifice outside the 

 lophophore.) 



Order I. GYMNOL^MATA. (Polypide destitute 

 of an epistome.) 



Sub-order I. Cheilostomata. (ZocBcium closed by 

 an operculum.) 



Families, ^teidce, Eucratidce, Gellularidce, Blcella 

 ridce, Notamidce, Gellaridve, Flustridce, Membrani- 

 jporidce, Mlcroporidce, Gribrilinidce, Microporellidcei 

 Porinidce, Myriozoidce, Escharidce, GelleporidcB. 

 * See note on page 201. 



