Chap. xiii.J 



FAUNA OF A BARRIER REEF. 



265 



its surface is remarkably even, and but few stunted corals were 

 growing upon it, but Alcyonarians were abundant, and the 

 whole surface was covered with a crust of calcareous seaweeds 

 ( Corailiftaceic). 



The water on the reef edge was usually not much more than 

 ankle-deep, but the breakers sent from time to time so strong 

 a current inwards across the barrier, that it was difficult to 

 keep one's footing. On the reef were resting irregularly 

 shaped masses of solid stony corals, portions of various 

 AstrcTidcF, PorifidcF, or of reef rock, thrown up upon the 

 marginal platform of the reef by the surf, and reminding one, 

 as they rested in all sorts of positions, of the scattered rock 

 fragments on a glacier. Sometimes they even rest on a 

 narrowed support like " table-stones," having become first 



ACROCLADIA MAMILLATA. 



cemented to the platform, and subsequently gradually under- 

 cut by the waves. Dana has figured such table-stones. These 

 thrown-up fragments are, as has been described, the only po - 

 tions of the actual reef which are visible from a distance. 



The chief differences between the fauna of the Fijian reefs and 

 those of Bermuda, are the absence on the former of any large 

 quantities of coral formed by Milleporida. and large branching 

 OculinidcT, and the absence of the large flexible Gorgonidie, 

 which form so striking a feature at Bermuda. The great 

 abundance of Madrepores forms the characteristic feature m 

 the Fijian reefs. I saw, however, at Fiji, no Madreporas so 

 large and fine in growth as those of St. Thomas. 



On the reef-margin, by turning over the cast-up rock frag- 

 ments, I found a few cowries, some huge Trocht, also specimens 

 of Turbo operculum, and other shells. Various Holothurians 

 and a large bright ultramarine-coloured Starfish {Ophidiaster), 



