46 Irwrtebrata. 



lamellar Fungia, the richly perforated Madrepores, and 

 the brain-corals, or Af&andrina. 



Sub- Class 2, Alcyonaria. The sea often casts on 

 the shore large, yellowish, gristly masses, known by 

 the fishermen as ' dead men's fingers/ but technically 

 named Alcyonium, which are types of the second sub- 

 class of Actinozoa. On placing this Alcyonium in sea- 

 water the surface sends forth from each pore a little 

 crown of tentacles. These are seen to be in circlets 

 around the mouths of minute polyps, and they differ 

 from the tentacles of sea-anemones in two respects ; 

 first, they are in multiples of four, usually being eight 

 in number, and, secondly, they are pinnately fringed, 

 that is, evenly toothed and lobed around the margin, 

 each little tooth having a hole at its tip : otherwise 

 the organisation is of the same type as that of a sea 

 anemone. Minute calcareous spicules are abundantly 

 scattered through the mass, and in some allied forms, 

 these, together with hard horny matter, make up a con- 

 tinuous, coral-like, foot- secretion in the axis of the 

 ccenosarc, as in the fan-corals or Gorgonias. In the 

 precious red coral of the Mediterranean, this axis is 

 of stony hardness ; and in Jsis, calcareous and horny 

 joints alternate with each other in the central axis of 

 the stem, thus combining firmness and flexibility. 

 The red organ-pipe coral of the Indian Ocean, with its 

 table-like partitions and its green polyps, belongs also 

 to this group. The feather-shaped sea-pens, which 

 are nearly related to the Gorgoniae, are not rooted, 

 but have the extremities of their stems buried in sand. 



Recapitulation. All the animals which make up 

 the sub-kingdom Coelenterata show a radiated arrange- 



