506 



STONY CORALS ; FUNGIA. 



imagine it composed of a number of Fungice packed closely 

 together. Here the same gradual consolidation of the lower part 

 of the cells takes place, as in the Caryophyllia; so that the mass 

 acquires considerable thickness. The cells of these Polypes do 

 not always, however, preserve their regular rounded form ; being 



sometimes oval, and in many 

 instances forming a long fur- 

 row, as in the Meandrina. 

 Each of the furrows, however, 

 is occupied by several Polypes 

 arranged side by side ; and 

 their point of junction is 

 usually indicated, either by a 

 slight transverse partition in 

 the furrow, or by a change in 

 the direction of the laminae 

 arising from its sides. In 

 the Meandrina cerebriformis 

 (brain-stone coral), the whole 

 mass, whether young or old, 

 is nearly hemispherical. It is 

 at first small, but extends in all directions by a process of growth 

 and consolidation analogous to that already described ; so that, 

 whilst its surface is always covered with a living flesh, and 

 studded with vast numbers of polypes, the interior is a mass of 

 solid limestone, the particles of which remain cemented together 

 by the animal matter in which they were at first deposited. 

 On breaking this hemispherical mass, the ridges which bound 

 the furrows may be traced inwards through its substance, even 

 to the central nucleus from which they commenced ; the deposit 

 in the interstices of these being of a softer character, and possibly 

 more of the nature of an exudation from the under surface of the 

 flesh. These Meandrince sometimes attain a considerable size. 

 Ehrenberg noticed single masses, in the Red Sea, from six to 

 nine feet in diameter. Their rate of growth, however, appears 

 to be slow. 



1074. It is principally by the animals of this group, that 



Fie.61 9. MASS OF ASTRJEA VIRIDIS ; a, a, 

 expanded Polypes .- b, b, Polypes with- 

 drawn into their cells ; c, stony mass 

 uncovered by flesh. 



