CORAL KEEFS. 119 



Where the slope is gentle, the great groups of living 

 corals and intervening spaces of white sand can be 

 still discerned through the clear water to a depth of 

 forty or fifty feet, beyond which the water recovers 

 its usual deep blue. A coral reef, therefore, is a mass 

 of inert matter, living only at its outer surface, and 

 chiefly on its lateral slopes." 



The quotation just made, may present less of the 

 picturesque than the reader might expect from pre- 

 ceding statements ; but it will not be so with the 

 following : 



" In a small bight of the inner edge was a 

 sheltered nook, where the extreme slope was well 

 exposed, and where every coral was in full life and 

 luxuriance. Smooth round masses of meandrina and 

 astraea were contrasted with delicate leaf-like and 

 cup-shaped expansions of explanaria, and with an 

 infinite variety of branching madreporse and serin- 

 toporae ; some with mere finger-shaped projections, 

 others with large branching stems, and others again 

 exhibiting an elegant assemblage of interlacing 

 twigs, of the most delicate and exquisite workman- 

 ship. Their colours were unrivalled vivid greens 

 contrasted with more sober browns and yellows, 

 mingled with rich shades of purple, from pale pink 

 to deep blue ; bright red, yellow, and peach-covered 

 nulliporaa clothed the masses that were dead, 

 mingled with pearly flakes of escara and retepora, 

 the latter looking like lacework in ivory. In among 

 the branches of the corals, like birds among trees, 



