594 vaughan: growth-rate of shoal-water corals 



The size of the colonies of all species of corals seems limited, 

 but some attain large dimensions, 2 to 3 meters or even more in 

 diameter, and nearly as much in height, while other species are 

 adult when a diameter of 35 to 50 mm. has been reached. Rec- 

 ords of two species, Favia fragum and Maeandra areolata illus- 

 trate relatively rapid growth for the first 2 to 4 years, after which 

 it decreases. Other species, for instance Orbicella annularis 

 and Maeandra strigosa are not so limited in size. Ramose 

 corals increase in dimensions more rapidly than massive species : 

 while of the former, the growth rate of species with perforate, 

 loose-textured skeletons is more rapid than that of species with 

 dense skeletons. In general the more massive and the denser 

 the corallum, the slower the growth; while the more ramose and 

 the more porous the skeleton, the more rapid the growth. 



table of indicated average annual growth-rate 



When practicable two diameters at right angles to each other 

 were measured in successive years, and the increments were 

 ascertained by subtracting the next earlier from the later measure- 

 ments. All increments for each species at each station were 

 added together and divided by the number of the annual incre- 

 ments entering into the computation. The averages for height 

 were similarly determined. As the records are for annual growth- 

 rate, each of the Bahama records is counted as 2, as each of those 

 represents a period of 2 years. 



It should be said regarding the nomenclature of the species 

 that the specimens designated Mussa (Isophyllia) dipsacea 

 Dana may include colonies of M. (Isophyllia) fragilis Dana. 

 The specimens referred to Porites clavaria Lamarck may include 

 more than one species of similar growth facies. 



As has been stated, the primary object of this investigation 

 was to get an approximate measure of the rate at which corals 

 might build reefs. In order to make this estimate, the true reef 

 corals must be considered separately from those which live in 

 other habitats. The reef species par excellence in the Recent and 

 Pleistocene reefs of Florida and the West Indies is Orbicella 

 annularis; after it in importance are Maeandra strigosa, M. 



