132 SOME WONDERS OF THE SEA. 



jecting tubercle. The spot on which each polype has 

 rested is marked in the stony skeleton by being the 

 centre to which all the little laminae converge. 

 1 If these polype-cells be examined with a tolerably 

 powerful lens, a wonderful beauty of structure will be 

 revealed, the little spicules of which the general mass is 

 composed being arranged with a regularity that wonder- 

 fully resembles the ice-crystals of the snowflake. 



Care must be taken to hold it in a good light; the 

 system on which the structure is based will then be 

 easily seen. 



Eound the edge of the aperture are ranged in order a 

 vast number of the white stony spicules of which the 

 mass is composed. 



Eadiating from the circumference towards the centre, 

 but not quite meeting, are six very delicate laminae. 

 When viewed directly from above, so that only their 

 upper edges are seen, they look very like the spokes of a 

 wheel, and indeed have been so represented in more than 

 one book, the artist having evidently drawn from a 

 microscopical preparation. If, however, we take a piece 

 of the Madrepore in our hands, and turn it about as we 

 are examining it with the lens, we shall find no difficulty 

 in tracing the laminae down to the extremity of the cell, 

 if we may so call it. 



As each of these cells was once inhabited by a living 

 six-armed polype, always keeping its beautiful tentacles 

 in motion, it is easy to imagine the extreme beauty of 

 the object when its living envelope is still encrusting it. 



