Plate 19. 



Fia. A. Aquarium at the laboratory, Tortugas, Florida. The jars on the lowest 

 shelf contained coral planulae that were being reared; the jars on 

 the next higher shelf contained clean seawater that was siphoned to 

 the jars below ; the jars on the top shelf contained coral colonies 

 from which the planulae for the rearing experiments were obtained. 

 B. Apparatus for planting corals. A, terra-cotta disc (8 inches in diam- 

 eter), to which corals were attached; B, iron bar, the lower end a 

 cap that fits over the heads of the iron stakes ; C, iron stake with a 

 terra-cotta disc in place on its head; D, sledge hammer. 

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