14 CLASSIFICATION OF THE ANIMAL KINGDOM. 



since it is certain that there exists an almost absolute identity of structure 

 between the flagellate zooids of the Sponges and the Flagellate Infusoria, 

 the reference of the latter to the Protozoa having never been called in 

 question. It may be added, that even if it were proved that the Sponges 

 were properly referable to the Metazoa, it would still require very much 

 more evidence than has yet been brought forward, before their relation- 

 ships with the Coelenterata could be reasonably admitted. Upon the 

 whole, therefore, it is probably best if only as a provisional arrange- 

 ment to regard the Sponges as a special division of the Protozoa, closely 

 allied to the Infusoria, but with sufficient peculiarities of their own to 

 entitle them to a special place and a special name (Porifera). 



(Oscar Schmidt, Die Spongien des Adriatischen Meeres, 1862, 1866 ; 

 Grundziige einer Spongien-fauna des Atlantischen Gebietes, 1870 ; and 

 Spongien des Meerbusen von Mexico, 1880. Carter, Notes introductory to 

 the Study and Classification of the Spongida, Ann. and Mag. Nat. Hist., 

 1875. Bowerbank, A Monograph of the British Spongidce, 1866, 1874. 

 Hseckel, Die Kalkschivdmme, 1872. Johnston, A History of the British 

 Sponges and Lithophytes, 1842. Saville Kent, Manual of the Infusoria, 

 1880-81. Zittel, Beitrage zur Systematik fossiler Spongien, Neues Jahrb. 

 fur Miii., Geol., und Paleont., 1877-78, and Handbuch der Paleontolo- 

 gie, 1879.) 



