Anthozoa 145 



REARING CORAL COLONIES FROM CORAL PLANULAE 



Thomas Wayland Vaughan, Scripps Institution of Oceanography 



DURING my field work on the corals of Florida and the Bahamas 

 from 1908 to 19 1 5, an endeavor was made to rear coral colonies 

 from planulae in order to ascertain the growth rates of young colonies 

 of the different species. Although the technique used in collecting and 

 rearing planulae and young colonies has been described in a number of 

 publications, all that is essential is contained in those at the end of this 

 note. 



The colonies from which it was hoped to obtain planulae were brought 

 from the sea into the laboratory and placed in glass vessels which were 

 deep enough for the specimens to be covered with seawater, but not so 

 deep as to interfere with noticing any planulae that were extruded. Since 

 the water on the parent colonies kept in the laboratory had to be pure, 

 it was necessary to change the water on specimens kept for several days. 

 This was easily done by siphoning the stale water from around the speci- 

 mens and pouring fresh water into the vessels. 



The planulae which were extruded were removed by pipettes and 

 transferred to vessels that contained objects on which it was expected 

 that they would settle. 



In my work on the corals of Tortugas, planulae were obtained from 

 five species, as follows: Astrangia solitaria, Favia fragum, Agaricia pur- 

 purea, Pontes clavaria, Pontes astreoides. The species with which 

 most success was obtained were Favia fragum and Pontes astreoides. 

 The duration of the free-swimming larval stage is variable both for the 

 same species and for different species. The duration for Favia fragum 

 was 6 to 23 days; Agaricia purpucea, 11 to 17 days; Pontes clavaria, 

 12 to 20 days; P. astreoides, 7 or 8 to 22 days. 



An effort was made to have the planulae settle on tiles (terra-cotta 

 discs) having a central perforation by which they might be fitted over 

 the heads of iron stakes. The tiles had a diameter of 8 inches and were 

 placed in jars, the inside diameter of which was about 8.25 inches and 

 the depth about 8.5 inches. After the bottom of a jar had been covered 

 with clean sand, a tile was placed in it and the central perforation and 

 the space between the periphery of the tile and the sides of the jar were 

 filled with sand to the level of the upper surface of the tile. As the 

 planulae tend to settle in depressions, it was necessary to fill these 

 spaces. After this preparation, fresh seawater was gently poured in 

 through a funnel until the jar was nearly full. The extruded planulae 

 were pipetted from the vessels containing the parent colonies and placed 

 in the culture jars. 



The water in the culture jars must be fresh and pure. It may be 



