1 84 TOILERS IN THE SEA. 



The great sea-fan of the West Indies often grows to 

 a yard in height and breadth, the branches and twigs 

 meet and coalesce, so as to form a regular net-work, 

 but in many other species the branches coalesce much 

 less frequently, or not at all, and then they resemble 

 clusters of slender twigs, or miniature shrubs or trees. 

 The general colour is often very bright, either red or 

 yellow, or violet, and must have an attractive appear- 

 ance, if they could be seen growing in their ocean 

 depths, attached to rocks, or to the sides of coral reefs. 

 The outer surface of the stems and branches of the 

 sea-fans is like a bark, and hence often called the 

 cortex, which may be peeled off like the bark of a 

 twig, leaving the hard and firm axis intact. This 

 bark is a continuous layer of the united polypes mixed 

 with minute granules, or spicules, of carbonate of 

 lime (to be described more fully shortly). The outer 

 surface is commonly smooth, but is sometimes covered 

 with small prominences ; where the latter are present 

 they are surmounted by the orifice, or oblong punc- 

 ture, through which the animal protrudes itself during 

 its life (fig. 35). 



Devotees to the use of the microscope, especially 

 those who employ it chiefly as a source of amusement, 

 usually include amongst their " beautiful objects " 

 preserved and prepared specimens of " spicules of 

 Gorgonia," which, being interpreted, implies that they 

 are the little granules of carbonate of lime secreted 



