[ 239 1 
fliell-fifli, by the wonderful conftrudlon of Its body, 
and the advantages which arife from it. But the differ- 
ence of make is not the only one, lince the fliell 
too is formed in a quite different manner. 
The feveral hypothefes of naturalifcs, on the for- 
mation of fhells, are known } fome will have them 
increafe by intuljujception^ and others by juxtapofition. 
This latter opinion, which M. de Reaumur patronized,, 
. and which nature feemed to juftify, became, in con- 
lequence, the moft general ; but if the friends of the 
other fyftem wcrethought to lofe their caufe,it was only 
for want of obferving with a fufficient degree of ac- 
curacy the operations of nature, whofe variety would 
have furnifhed them with inftances in their favour.- 
Our bivalve infedt offers one, which the defertion of 
the old fliell and the formation of a new one, in pro- 
portion as the animal grows, put beyond a doubt.^ 
The fadl itfelf appears, not only from the obfervatioa 
of empty fhells of different fizes, which are to be 
met with in waters, and are nothing more than the 
fpoils of our bivalve infedts; but, from the lingular 
good fortune I had, in feeing one of the animals drip 
itfelf, entirely, in my prefence, of the membrane of 
its fhell, and of the exterior parts of its body, and fliew 
itfelf at lad before me abfolutely renewed. The 
exiivice both of the died and the animal’s body were- 
tranfparent as the brighted c^’yftal. The joints of 
the anteniKt^ the bridles, the feet, the fmalled hairs, 
were more didinguidaable than in the animal itfelf.. 
How infinitely fmall are the organs, which, hid as it 
were in dieaths and cafes, only become vifible when 
they are magnified fome thoufands of times ! and 
•how many are there which efcape the bed microfeope! 
Ill 
