[ 457 } 
are truly zoophytes, formed by the labour of the ani- 
mals, which inhabit them, and to which they are 
the day and fupport. 
By what is exhibited in this work, the author con- 
ceives, that he has explain’d the nature of thefe feveral 
marine productions, which have hitherto been fo 
enigmatical. It is true indeed, that no reafons can be 
affign’d, why the oeconomy of thefe animals is di- 
rected in fuch or fuch particular forms. We can no 
more account for the admirable itruCture and colour 
of feveral fpecies of fhell-fifh : we mull in this, as 
in mod of the other operations of nature, cry out, 
O altitudo divitianm ! 
Swammerdam feems to have proceeded very far 
in thefe difcoveries, as you may fee by his letter to 
Bocconi*. He goes farther, and fays, that having 
with a microfcope examin’d a piece of coral, he 
found, that each particle thereof was compofed of ten 
or twelve angular and chryitalline fpherules ; and 
having faw’d acrofs a piece of coral, and given it 
the higheft poliffi, he found with the microfcope, 
and even without it, that coral from its centre is dif- 
pofed in ftrata , which he conjectures are form’d by 
the application of the above-mention’d fpherules. 
M, de Reaumur, having been made acquainted 
with what M. de Peyffonnel had obferv’d, fent him 
a letter thereupon in the year 1726 j wherein he 
takes notice, that no one had hitherto confider’d 
coral as the work of infeCts. But it feem’d to him 
difficult to edabiiffi this doCtrine in the generality of 
M m m marine 
* Lettre xix. fol. 164. 
