ANNOTATIONS AND ADDITIONS. 73 



"Enappelant Inattention des naturalistes sur les animalcules 

 des coraux, nous esperons demontrer que tout ce qu'on a 

 dit ou cru observer jusqu'a ce jour relativement aux im- 

 menses travaux qu'il sont susceptibles d'executer, est le plus 

 souvent inexact et toujours excessivement exagere. Nous 

 pensons que les coraux, loin d'elever des profondeurs de 

 Focean des murs perpendiculaires, ne forment que des 

 couches ou des encroutemens de quelques toises d'epaisseur." 

 Quoy and Gaimard also propounded (p. 289) the conjec- 

 ture that the Atolls, (coral walls enclosing a lagoon) , pro- 

 bably owed their origin to submarine volcanic craters. 

 Their estimate of the depth below the surface of the sea 

 at which the animals which form the coral reefs (the species 

 of Astrsea, for example) could live, was doubtless too small, 

 being at the utmost from 25 to 30 feet (26^ to 32 E.) An 

 investigator and lover of nature who has added to his own 

 many and valuable observations a comparison with those of 

 others in all parts of the globe, Charles Darwin, places with 

 greater certainty the depth of the region of living corals at 

 20 to 30 fathoms. (Darwin, Journal, 1845, p. 467 ; and 

 the same writer's Structure of Coral Reefs, p. 84-87 ; and 

 Sir Robert Schomburgk, Hist, of Barbadoes, 1848, p. 636.) 

 This is also the depth at which Professor Edward Eorbes 

 found the greatest number of corals in the Egean Sea : it is 

 his " fourth region" of marine animals in his very ingenious 

 memoir on the " Provinces of Depth" and the geographical 

 distribution of Mollusca at vertical distances from the 

 surface. (Report on ^Egean Invertebrata in the Report of 

 the 13th Meeting of the British Association, held at Cork 

 in 1843, pp. 151 and 161.) The depths at which corals 



