2 INTRODUCTION. 



these vast rings of coral-rock, often many leagues in 

 diameter, here and there surmounted by a low verdant 

 island with dazzling white shores, bathed on the out- 

 side by the foaming breakers of the ocean, and on the 

 inside surrounding a calm expanse of water, which, 

 from reflection, is generally of a bright but pale green 

 colour. The naturalist will feel this astonishment 

 more deeply after having examined the soft and almost 

 gelatinous bodies of these apparently insignificant 

 coral-polypifers, and when he knows that the solid reef 

 increases only on the outer edge, which day and night 



No. 1. 



is lashed by the breakers of an ocean never at 

 rest. Well did Francois Pyrard de Laval, in the 

 year 1605, exclaim, ' C'est une merueille de voir 

 chacun de ces atollons, enuironne d'un grand banc de 

 pierre tout autour, n'y ayant point d'artifice humain.' 

 The above sketch of Whitsunday Island, in the 

 S. Pacific, taken from Capt. Beech ey's admirable 

 Voyage, although excellent of its kind, gives but a 



