RANGE IN DEPTH OF CORALS. 



91 



islands ; and through all these regions no evidence was 

 obtained of corals living at a greater depth than fifteen or 

 twenty fathoms. Within the reefs west of Viti Lebuand 

 Vanua Lebu, the anchor of the Peacock was dropped sixty 

 times in water from twelve to twenty-four fathoms deep, and 

 in no case struck among growing corals ; it usually sunk into 

 a muddy or sandy bottom. Patches of reef were encountered 

 at times, but they were at a less depth than twelve fathoms. 

 By means of a drag, occasionally dropped in the same channels, 

 some fleshy Alcyonia and a few Hydroids were brought up, but 

 no reef-forming species. 



Outside of the reef of Upolu, corals were seen by the writer 

 growing in twelve fathoms. Lieutenant Emmons brought up 

 with a boat-anchor a large Dendrophyllia from a depth of 

 fourteen and a half fathoms at the Feejees ; and this species 

 was afterwards found near the surface. But Dendrophyllia, it 

 may be remembered, is one of the deep-water genera. 



These facts, it may be said, are only negative, as the sound- 

 ing-lead, especially in the manner it is thrown in surveys, would 

 fail of giving decisive results. The character of a growing 

 coral bed is so strongly marked in its uneven surface, its deep 

 holes and many entangling stems, to the vexation of the sur- 

 veyor, that in general the danger of mistake is small. But 

 allowing uncertainty as great as supposed, there can be little 

 doubt after so numerous observations over so extended regions 

 of reefs. 



The depth of the water in harbours and about shores where 

 there is no coral, confirms the view here presented. At Upolu, 

 the depth of the harbours varies generally from twelve to 

 twenty fathoms. On the south side of this island, off Falealili, 

 one hundred yards from the rocky shores, Lieutenant Perry 

 found bare rocks in eighteen and nineteen fathoms, with no 

 evidence of coral. There is no cause here which will explain 

 the absence of coral, except the depth of water ; for corals and 

 coral reefs abound on most other parts of Upolu. Below 

 Falelatai, of the same island, an equal depth was found, with 

 no coral. Off the east cape of Falifa harbour, on the north 



