140 ANTIIOZOA ASTEROIDA. 



away irregularly, but wlien the branches inosculate and form 

 a sort of net, they become Sea-Fans, which some naturalist, 

 of more than our usual fancy, has approjDriated to the use of 

 Venus — Flabellum Veneris.* 



In every polypidom of this order there are three parts which 

 require notice, — the polypes, the fibro-fleshy calcareous crust 

 in which they are placed, and the internal axis. The connec- 

 tion between these parts is indissoluble; and although we may 

 treat of them separately, and as if they were somewhat inde- 

 pendent, yet we must guard against the entertainment of any 

 such opinion. It was once indeed a debated question whether 

 each polypidom might not rightly be considered a mere aggre- 

 gation of separate animalcules, but all that we know of their 

 habits and structure goes to prove the contrary ; so that no 

 one probably now disputes that the polypidom with its polypes 

 constitute but one body, the latter being in the place of as 

 many mouths and stomachs scattered over the surface. The 

 whole mass, with the exception at most of the axis in those 

 which 2)ossess a stony or horny one, is living and organized, re- 

 ceiving the material of its nourishment and growth from the 

 food captured and digested by the polypes ; and as they have 

 not only an orgauical union with the irritable flesh in which 

 they are immersed, but are many of them more intimately as- 

 sociated together by means of canals and intestines, so they 

 participate in every benefit and every evil. When, therefore, 

 one pinna of a Sea-Pen is lacerated or cut away, the remain- 

 ing pinnae gradually shrink, the polypes withdraw, and the 

 whole body contracts in every dimension ; or if a portion of 

 the Alcyouium be subjected to irritation, the gradual collapse 



* Ray has especially called attention to the fan-like growth of submarine bodies. 

 " Tliat the motion of the water descends to a good depth, I prove from those plants 

 that grow deepest in the sea, because they all generally grow flat in manner of a fan, 

 and not with branches on all sides like trees ; which is so contrived by the provi- 

 dence of nature, for that the edges of them do in that posture with most ease cut the 

 water flowing to and fro ; and should the flat side be objected to the stream, it 

 would soon be turned edge-wise by the force of it, because in that site it doth least 

 resist the motion of the water ; whereas did the branches of these plants grow round, 

 they would be thrown backward and forward every tide. Nay, not only the herlia- 

 ceous and woody submarine plants, but also the lithophyta themselves aftcct this 

 manner of growing, as I have observed in various kinds of coral and pori." — The 

 Wisdom of God in the Creation, p. 77. 



