704 



llADIATA. 



by the canals which connect the stomachs of tne polypes imDedded in 

 stem has a jointed character, being composed alternately of 

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

 F;in)and Antipathcs (l^lack Coral) it is altogether horny; the 

 investing substance, however, being furnished with a large 

 number of spicules, forming a friable crust, in .which the 

 orifices fur the polypes nuty be frequently discerned, when 

 diied upon the horny axis. In some few cases, instead uf 

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

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

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

 Pauiatuhi, orsea-jien, and with the Vart:tUlum, which is nearly 

 allied to it (Fig. 14). 



The order may be subdivided into the following families :■ — 

 Section A. Polype-mass fixed. 



Family 1. Alcyonidce. Polype-mass coriaceous or some- 

 what carneuus, without any distinct axis, but 

 strengthened by variously-disposed calcareous 

 spicula ; polype-cells subcutaneous, scattered over 

 the surface. 



Family?. Corallidcc. Polype-mass arborescent; polypes 

 scattered over the whole surface, imbedded in a 

 thick eretaceo-gelatinous cclluiiferous crust; the 

 axis solid, horny, or calcareous. 



Family 3. Tubiporido:, Polypary composed of calca- 

 reous tubes, arranged in successive stages; polypes 

 terminal. 

 Section IJ. Polype-mass free. 



Family 4. J'mnatidida:. Polype-mass jtcnnated, carneous • 



its fluDstance. In the Tsh ITippuns, tha 



Fig. 18.— Red Coral. 



the skin spiculiferous ; the axis bony, 

 tinuous; polypes arrangL-d along a part only of the polypary, of which a portion is sometime 



simple, con- 

 s cmbeddcd- 



Fh). 19. — YCRETILLUM 



T(i order to bring the enumei'ation oi f;imiliep and genera contained in the text into hamirmy with modern views, 

 the following tahli; of Cuvier's arrangement, showing the real situatiuti of each pi'incipal group, may be useful. 



Oraer I.— Caenusi ; Arthda- '^ ^y^^^^^ 11.— IlELiANxnoiDA ; Fam. 1 and 2. Jctiniad'M and Zoanthidcc. 



Lnccr)iari.a. J 



Order II.^-Gelatinosi ; ' I/i/dra. Order I. — IU'i»boida ; Fam, 1. I/i/drak(>.v. 



Order m.^CoRALLIFEIil. 



Order III. — Asteeoiea ; Fam. 3. Tiihiporldce. 

 Order I. — Htdeoida ; Fam. 2. Tuhularidm. 

 Order I. — IItdroida ; Fam. 3. Sei-tutaridce. 

 BJiYOZ'tA of various families. 

 Belong tn the Vegetable kingdom. 

 Order III.-^Astekoida ; Fam. 2. CoralUdce. 

 Ordur III. — AsTEEOiDA ; Fam. 2. CoralUdcr. 



Order II.— Helianthoida ; Fam. 3 and 4. Madrcphyllid'C and MadrepoHdm. 

 Cliiefly BRYOZOA of various families. 

 Order II. — AsTERoiDA ; Fam. 4. P'innatulid'iE. 

 Order II. — Asteroida ; Fam. 1. Alci/Onuia;. 

 PORIFEBA, 



Tubipora. 



Ttibidaria. 



Scrtulorla. 



CdUh I, -li. 



CoraUhnx. 



Ceratop]n/fa. 



Litkophifta,—Ish, li'G. 



Madrcpora. 



MiUipora. 



Pennatul/i. 



A Icyordum. 



Spovgia. 



" Of the genera associated by Cuvier under this order. Cor i)m is the only one that is really allied to Hydra ; 

 CHstatiMa being a Bryozoun ; VortkdUi being an Infusory Animalcule ; and Pedkdkiria not being a separate 

 animal, but an appendage of certain Echinodermata. 



