LOWER PENINSULA. 



CLASSIFICATION OF POLYPES. 



BY MILNE-EDWARDS. 



I. Cor a Ilia. 

 II. Hydroida: soft, not represented in fossil condition. 



The Corallia are divided into three orders: 



1. ZoantJiaria. 



2. Alcyonaria. 



3. Podactinaria. 



Of these, the first order includes the principal part of all the fossil 

 corals; the second is only represented by Graptolites, and the third 

 has no palaeozoic representative. 



The Zoantharia are divided into seven sub-orders : 



1. Malacoderma : soft, not fossil. 



2. Apora : recent coralline forms. 



Milne-Edwards placed the genus PalcEocycliis with this sub-order, 

 but its aflfinities are decidedly nearer to forms placed in another sub- 

 order, the Z. rugosa. 



3. Perforata. — Abundantly represented in the mesozoic and re- 

 cent coralline fauna, but not in the palaeozoic. The genus Protaraea, 

 placed here by Milne-Edwards, belongs to the next following order, 

 the tabulata, and the genus Pkurodictium, likewise enumerated 

 among the Zoanth. perforata, is created by simply mistaking the 

 casts of a Michelinia for a particular type of organization, very ap- 

 propriately connected with the specific by-name of " proble7naticwn.'" 



4. Tabulata. 



5. Rugosa. 



These last two orders comprise nearly all palaeozoic corals, and 

 will form the special object of consideration in subsequent pages. 



6. Tubulosa. — An order formed to include the genus Aulopora 

 and Pyrgia, both of which genera are in intimate relationship with 

 certain types placed under the Zoanth. tabulata, with which I am 

 going to describe them. 



7. Zoanth. caulicula. — These have no representatives of palaeozoic 

 date. 



Zoantharia tabulata. — The corals comprehended under this sub- 

 order are composed of tubular polyp cells, septate by transverse 



