202 THE BOTTOM OF THE SEA. 



in the lied Sea,* but are still more frequent in the 

 equatorial seas, where their size and their general 

 aspect have suggested the name by which they are 

 sometimes called by sailors — Nejptunes Brain, A 

 specimen in the British Museum is four feet in circum- 

 ference. Their great size is accounted for by the 

 manner of their formation. " As one fleshy mass ex- 

 pires/' observes Dr. Mantell, " another appears and 

 gradually expands, pouring out its calcareous secre- 

 tion on the parent mass of coral : thus successive gene- 

 rations go on accumulating vast beds of stony matter, 

 and lay the foundation for coral reels and islands." As 

 remarked in Lyell's *' Principles of Geology," " We 

 may compare the operations of the zoophytes in the 

 ocean to the effects produced on a smaller scale on 

 land by the plants which generate peat ; in wliich the 

 upper part of the sj)haffnum vegetates, while the lowt r 

 is entering into a ndneral mass, in which the traces of 

 oi'ganisation remain when life has entirely ceased. In 

 corals, in like manner, the more durable materials of 

 the generation that has passed away serve as the 

 foundation on which their progeny are continuing 



* " The whole bed of this extensive basin of water is absolutely 

 a forest of submarine plants and cojals. Here are sponges, madre- 

 pores, corals, fungisB, and otlier pnlyparia, with fuci, iilgse, and all 

 the variety of marine vegetation, covering every part of the bottom, 

 and presenting the appearance of a submarine garden of the most 

 exqui^iite verdure." — Mantell. 



