CORAL. • (ill 



iilanii iiiid t'<»l(liii_«4' itself iq) with tlu> ^reiiti'st cusc, so us to t)e tihnost 

 iiidistinguishable from '(h<> sarppsoine, it tluMi sho-ws on the surface 

 only as a sliglit. barely \isibl(\ iii[)])le-like projection. When expanded 

 it bears at its sunnnit (Mght didicate tentacles, with fringed borders, 

 that can be moved about in evvvy direction. The body itself, C3din- 

 drical in form, consists oidy of a delicate, transparent wall surround- 

 ing a spacious cavity, divided into compartuKMits l)y eight vertical 

 septa. This internal sac opens externally 1)V a mouth in th(> middle of 

 the space surroundc^l by the tentacles; at the other extremity it is 

 prolonginl as a canal that extends into the Harcosom(\ ramities there, 

 and unites with similar branches that originate from neighboring 

 polyps. All interconimunicatx^ l)y means of these canals. The entire 

 assem)>lage is a colony, a polyp community in which each individual 

 is joint-stock owner. Not oidy does theii' common skideton sustain 

 them all alike, the food seized ])y the tentacles of one dot>s not nourish 

 him alone, he shares it with his neighbors. They subsist upon small 

 creatures which are digested and rendered assimilable in the interior 

 cavity of the body. The polyps annually produce eggs upon the thin 

 septa which divide this interior cavity. After fecundation is accom- 

 plished these eggs go on to develop without leaving the cavity, becom- 

 ing free-swimming larva' resembling microscopic worms whose surface 

 is covered with vibratile cilia. These embryos swim about in the 

 maternal cavity, finally pass out of the mouth, abandon their singular 

 shelter, and wander forth at random. These beings are of such 

 elementary structure that one organ performs all their functions. 



Many of these larva' are pursued, seized, and eaten by marine crea- 

 tures stronger than they. Those which escape fix themselves, after a 

 period of vagabond existence, to a rock or a shell and there become 

 modilied into polyps, growing external tentacles and internal septa. 

 Then each polyp, far from remaining solitary, produces at its base 

 expansions or buds which increase, develop, and in turn become 

 polyps. This budding gives rise to a 3'omig colony, as yet minute and 

 spread out over its support. The little sarcosome then commences to 

 display its peculiar activity. It forms by secretion an outline of a 

 calcareous skeleton, which it attaches to the support and constantly 

 enlarges l)y the addition of new layers. On this it erects itself as on 

 a protu])erance. The colony contiimes to bud, the sarcosome to 

 increase and to deposit new calcareous matter. The skeleton enlarges, 

 elongates, and ensheaths itself with sarcosome, which constitutes for it 

 an axis of support, this term being often used to designate it. It 

 ramifies. The polyp conununity thus aiises; it constantly increases, 

 and it derives its oi-igin fi'om the minute lai'va engendei'cd by one of 

 the polyps of a neighl>oring comnuimty. 



