91 
*»'ieb in their most perfect condition are well defined and 
' ,8 tinct from each other, become confused, from having inter- 
vening depressions filled up with calcareous matter, and the 
'nterspaees or meshes on the surface disappear from the same 
jause. In this wav all the specific characters are destroyed ; 
.. e surfaces become plain and even, and the apertures look 
,'ke minute orifices in a plain incrustation. The apertures, 
'•te the surface, loose their specific distinctions and become 
'"’aller, till bv the continued deposit of calcareous matter, 
’ lp .V become obliterated and the polypes thus become en- 
c *°sed in graves of their own making. This being the ease, 
I further effusion of pulp takes place on the surface of the 
destroyed cells; in it new cells and polypes are. developed, 
.? be again destroyed by the very process which gave them 
Thus we see 
•* > — The living pile ascend. 
The mausoleum of its architects. 
Still dying upwards as their labours closed.” 
^ r °m these repeated obliterations it is, that many species 
c orne so irregular in shape; a remarkable instance oi which 
s found in the common pumice stone coralline, ( Ccllcpora 
P '">«cosa.) 
We thus see that the external surface of the cells is per- 
[| L ‘. l,, ally undergoing changes of a very marked character. Is 
“■ s consistent with an extravascular and inorganic character? 
these calcareous cells, in reality have bo organic cha- 
but are merely formed by, or are an exudation from 
4 f® Pulp, or from a secreting membrane, it is evident, that 
!' p their first formation they could undergo no alteration 
,.i " er in form or characier, except what would arise from a 
e e, <iical or mechanical change in their structures. The 
p l, roal surface once formed, would remain for ever beyond 
t)i e influence of the polype within. If inorganic bodies be 
.funded by highly organized tissues, life is sometimes 
gently powerful to cause their removal. But in the case 
er consideration, the lime is not moulded on the pulp, by 
i^Otle, as in shells; but is formed in and by the pulp 
lav au< l a continued deposition is going on. If the external 
be beyond the influence of life, the lime ought lobe 
WiJi si, cd on the internal surface as being most in contact 
Vir 0| * l be exuding pulp, and thus, the cavity of the cell 
e x , uk ‘ become filled and solid, rather than the fissures of the 
But the exact reverse of this is the case. In 
</ (( , species, such as Calepora cervicornis, and ramulosa, 
Mats; Eschar a foliacea, and others, the whole pro- 
o|, U °f formation, from the embryo, to the perfect and 
*C , f aled ceils - can be observed ; so that no difficulty can 
*°r want of opportunities to test these opinions. In 
