BOOK SECOND, 



POLYPI. 



CLASSIFICATION. 



§ 24. 



The Polypi are either immovably fixed, or seated on a locomotive 

 foot. Their soft body is in part enveloped by a solid support, the 

 polypary. This last is often, for the most part, horny or calcareous ; and 

 by it numbers of these animals are united into greater or less groups. The 

 central mouth is always surrounded by a coronet of contractile tentacles. 

 The digestive apparatus is organized after two diiferent types, upon which 

 is based a division of these animals into two orders. The sexual appara- 

 tus is always without copulatory organs. 



ORDER I. ANTHOZOA. 



The digestive canal is without an anus, and opens into the general 

 cavity of the body. 



Family : Madreporina. 



Genera : Ocidina, Millepora, Madrepora, Caryophyllia, Astraea, Desmo- 

 phyllum, Maeandrina, Monticularia, Agaricia, Favia. 



Family : Gorgonina. 

 Genus: Gorgo7ua. 



Family : Isidea. 



Genera : Corallium, Isis. 



Family: Tubiporina. 



Genus: Tubipora. 



Family : Alcyonina. 

 Genera: ^Icyonium, Lobularia, Alcyo7iidium. 



Family : Pennatulina. 

 Genera : Vereiillum, Pennatula, Virgvlaria. 



