704 



KADIATA. 



by the canals which connect the stomachs of tne polypes imoeddea in Its suDstance. In the Is'tt Hippuru, the 

 stem has a jointed character, being composed alternately of 

 calcareous and of horny matter. And in the Goryonia (Sea- 

 Fan) and Antipathes (Black Coral) it is altogether horny ; the 

 investing substance, however, being furnished with a large 

 number of spicules, forming a friable crust, in iwhich the 

 orifices for the polypes may be frequently discerned, when 

 dried upon the horny axis. In some few cases, instead of 

 being attached by roots to fixed bodies, the Alcyonian poly- 

 pidoms are free, being carried about by the action of the 

 waves and currents of the ocean. This is the case with the 

 Pennatula, or sea-pen, and with the VeretiUum, which is nearly 

 alUed to it (Fig. 14). 



The order may be subdivided into the following families : — 

 Section A. Polype-mass fixed. 



Family 1. Alc'jonidce. Polype-mass coriaceous or some- 

 what carneous, without any distinct axis, but 

 strengthened by variously-disposed calcareeus 

 spicula ; polype-cells subcutaneous, scattered over 

 the surface. 

 Family 2. CoraUidm. Polype-mass arborescent ; polypes 

 scattered over the whole surface, imbedded in a 

 thick cretaceo-gelatinous celluliferous crust; the 

 axis solid, horny, or calcareous. 

 Family 3. Tubiporidie. Polypary composed of calca- 

 reous tubes, arranged in successive stages ; polypes 

 terminal. 

 Section B. Polype-mass free. 



Family 4. Pemiatulid<e. Polype-mass pennated, carneous ; the skin spiculiferous ; the axis bony, simple, con- 

 tinuous ; polypes arranged along a part only of the polypary, of which a portion is sometimes embedded- 



Fig. 13.— Ked Coral. 



Order I. — llronoiDA. ; Fam. 1. Hydraidce. 



Fio. 19.— Vebetillum 



In order to bring the enumeration of families and genera contained in the text into harmony with modern views, 



the following table of Cuvier's arrangement, showing the real situation of each principal group, may be useful. 



Order I.— Caenosi ; Actinia. \ Order II.— IIelianthoida ; Fam. 1 and 2. Actiniada: and Zoanthidw. 



Lueemaria. 

 Order II. — Gelatinosi ; • Hydra. 

 Order III.— Corallifebi. 



Order III, — Asteboida ; Fam. 3. Tubiporidco. 



Order I. — Htdroida ; Fam. 2. Tubularidcc. 



Order I.— Htdroida ; Fam. 3. SertularidcB. 



BRYOZOA of various famihes. 



Belong to the Vegetable kingdom. 



Order III.^Asteroida ; Fam. 2. Corallidfe. 



Order III.— Asteroida ; Fam. 2. CoraUidm. 



Order II. — Helianthoida ; Fam. 3 and 4. Madrephyllidie and Madreporida: 



Chiefly BRYOZOA of various families. 



Order II. — Asteeoida ; Fam. 4. Pennatulidcc. 



Order II. — Asteroida ; Fam. 1. AlcyonidcB. 



PORIFERA. 



Tubipora. 



Tubularia. 



Sertularia. 



CeUularia. 



CoraUina. 



Ceratophyta. 



Lithophyta, — Isis, &c. 



Madrcpora. 



MUlipora. 



Pennatula. 



Alcyonium. 



Spongia. 



* Of the genera associated by Cuvier under this order, Coryne is the only one that is really allied to Hydra ; 

 Cristatclla being a Bryozoon ; Vorticella being an Infusory Animalcule ; and Pedkdlaria not being a separate 

 animal, but an appendage of certain Bchinodermata. 



