[ 8o 5 ] 
fome very fmall, in others fcarce or not at all vi- 
able. 
Thefe, I think, are the main difficulties, all which 
I ffiall endeavour to elucidate; but muff firft ac- 
knowlege myfelf obliged to Monfieur de Peyfonnel, 
and particularly to my worthy and ingenious friend 
Mr. John Ellis, F. R. S. for their curious obferva- 
tions on the nature of coral, upon which this latter 
part of my hypothecs is founded. They have, I think, 
plainly demonftrated, that many bodies which we 
always took to be vegetable from their appearance, 
are really animal, and conftrudted by the polyp ; and 
that feveral coralline fubftances, hitherto reputed 
marine plants, are thick befet with a prodigious 
quantity of feedling-fhells (too fmall for the naked 
eye to fee), clofe by each other, as diamonds in a 
bodkin, ready to come forth in due time out of their 
feveral nefts or cellules ; fee Philofophical Trans- 
actions, Vol. 47. pag. 444. and Vol. 48. Tab. V. 
pag. 1 1 7. Whereupon I very humbly fubmit, if it is 
not highly probable that the teftaceous tribe in gene- 
ral are generated like butterflies, and flies of all 
kinds, the one from a maggot, the other from a 
polyp ? Nay, it appears prefumptive to me, that it 
moft be fo with a great many. On which circum- 
ftances I proceed, that as corals in general, from late 
obfervation, feem to be conftruCted by polypi, what 
inconffltency then to believe them to be the primary 
Rate of all or mod of the teflaceous tribe ? If fo, it 
is almoft beyond a conjecture, that the body called a 
belemnites (which, on being put into acids, is found 
to ferment in like manner as coral, and other creta- 
ceous 
2 
