Mr. Hunter’s Anatomical Remarks 
In the Leach, Polypi, &c. may depend upon fome circumdance In 
the animal oeconomy which we are at prefent not fully ac- 
quainted with. 
The univalves, whofe bodies are under fimilar circumdances 
rcfpectmg the (hell with this animal, have the iritedine receded 
back, and the anus, by that means, brought near to the exter- 
nal opening of the (hell, the more readily to difcharge the ex- 
crement; and although this dru&ure, in thefe animals, appears 
to be folely intended to anfwer that purpofe, yet when we find 
the fame (lr ubture in the black Snail, which has no (hell, this 
rea foiling will not wholly apply, and we mud refer it to fome 
other intention in the animal oeconomy. 
In this animal we muft therefore reft fatisfied that the disad- 
vantageous (Ituation of the anus, with refped to -the excrement’s 
being difcharged from the (hell, anfwers dome purpofe in the 
oeconomy of the animal, which more than counter-balances the 
inconveniences produced by it. 
It would appear,, from confidering all the circumdances, 
that the excrement thrown out at the anus muft pafs from the 
tail along the infide of the tube, between it and the body of 
the animal, till it comes to the external opening of the (hell, as 
there is no other evident mode of difcharging it. 
How the tube or (hell is formed in ftone or coral is not eafily 
afcertained. It may be afked, whether this animal has the 
power of boring backwards as the Teredo Navalis probably 
does, or whether the (lone or coral is formed at the fame time 
with the animal, and grows and increafes with it; and if we 
cendder all the circumdances, this lad would appear to be mod 
probable, and agree bed with the different phenomena ; for the 
coral is lined with a (hell, which could not be the cafe if the 
animal was .continually increafing this hole, both in length and 
i breadth, 
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