CORAL REEFS 



i6i 



future only to maintain and reproduce itself, but if it is a 

 colonial, reef-building coral it is only in the very earliest 

 stages of its development. Division begins after the fashion 

 shown in Figure 33, small individuals budding off from the 

 side of the first-formed polyp. This may then continue 

 to grow upward, increasing the height of the limy column, 

 and budding oflf side polyps as it goes, the original polyp 

 forming the apex of the whole colony. In another type of 

 coral growth, the apical polyp, instead of being the original 

 and oldest one, is the youngest, having been budded off 

 from the polyp immediately beneath it and shortly to be 

 superseded when it 

 produces a bud in 

 its turn. Many 

 other corals have no 

 specialized point of 

 growth, all the polyps 

 having equal powers 

 of division and bud- 

 ding, and in these 

 cases the colony 

 spreads in a regular 

 fashion over the sur- 



jr^^^ ^( r.*-^^r^<^ ^-^A Fig. 33.— Diagram showing method of budding of Coral 

 face of stones and ^ (after VVood-Jones). 



underlying dead 



coral, finally forming a rounded mass such as that usually 

 assumed by the important reef-building Porites. In some 

 cases the division of the polyps may not be complete ; 

 instead of the surface of the colony being studded with 

 many little round polyps, aU quite distinct from one 

 another, it may be covered with wandering, sinuous 

 grooves all fringed with the characteristic septa and repre- 

 senting the site of polyps which have extended themselves 

 as it were, budded off but never parted company with the 



