524 A NATURALIST OX THE "CHALLENGER." 



The orange, lemon, and lime, which grow wild all over Tahiti, 

 do not appear to deteriorate at all in quality, nor in quantity of 

 fruit, although in the ferine condition. The fruit almost appears 

 finer and better for running wild. The oranges we all pro- 

 nounced the best we had ever eaten. The limes lay in cart- 

 loads upon the ground, rotting in the woods. It would pay well 

 to make lime-juice for export in Tahiti. Some native insect 

 must have adapted itself completely to the blossoms of the 

 orange tribe as a fertilizer, so abundant is the fruit. Vanilla, 

 which is cultivated in the island with success, requires, as every- 

 where else away from its home, to be fertilized by hand. 



A Mushroom Coral (Fungia) is very common all over the 

 reefs at Tahiti. After much search, I found one of the nurse- 

 stocks from which the disc- shaped free corals are thrown off as 

 buds, as was originally shown by Stutchbury, and confirmed by 

 Semper, who considers the case to be an instance of alternation of 

 generations.* 



Though the free corals were so extremely numerous, I could 

 only find the one nurse mass. It, as in Stutchbury 's specimen,f 

 consisted of a portion of a very large dead Fungia, to which were 

 attached all over numerous nurse stocks in various stages of 

 growth. Some of those in the specimens have only just de- 

 veloped from the attached larva, and have as yet thrown off no 

 buds. A small cup-like Coral is formed, and as it grows the 

 mouth of the cup widens and assumes somewhat the form of 

 the adult disc-shaped free Coral, but is still distinctly cup- 

 shaped. A line of separation forms in the stem of this bud, 

 and the bud falls off; a fresh bud then starts from the centre of 

 the scar left by it on the stock, and the process is repeated. 

 The fresh bud in its growth does not spread its attachment over 

 the whole surface of the old scar, the margins of which persist 

 as a dead zone around its base. 



The line of separation of the second bud does not cor- 

 respond with that of the first, but is beyond it a short distance. 



* Semper, " Generationswechsel bei Steinkorallen," Zeitschrift fur Zoo- 

 logie, 22. Bd. 1245. Leipzig, Engelmaim, 1872, s. 36. 



t G. Stutchbury, " An Account of the mode of Growth of Young 

 Corals of the Genus Fungia." Trans. Linn. Soc, Vol. XVII. 1830, p. 493. 



