( »«<S ) 
ter*. Yeti am apt to believe, the fe Teeth as well as the Rudi- 
merit a, have been d prima formatione, and that becaufe, i . The 
Jaw bone fo firmly adheres to the Teeth on both Tides To Toon 
as they appear, and the place of their Roots is fo well known 
fby the Protuberance on the outfide of the Jaw) to be enlarg'd 
within the Alveoli , that I do not fee how they can be expell’d 
by a fucceeding Set. 2. When one Set of Teeth expels the other, 
the fecond is ufually below the firft, and not plac'd in the fame 
R.ank, as thefe are*, which obliges me to enquire, what may be 
the ufe of thefe Rudiment a : Which I fuppofe to be, 1. To fill up 
the Cavity of the Lower Jaw. 2. By their Weight to add Strength 
in Maftication. 3. That there may be lo many different Bo; s to 
aflift the Teeth in their motion ^ and s thly, To ferve infteau o: a 
Wedge for- keeping the Teeth firm in their Place. For the firft, - 
’twas convert ent the Lower Jaw Ihould bear an equal proporti n 
in its bignefs to the Upper, and have fufficient fpace for Infer 
tion of the Mufcles fit for its Motion ; and if a proportionable 
bignefs, than either the Bone muft be altogether folid, or cuvous 
and ftulF’d- with fome other ponderous Subftance ; for if fpcngy 
or cellulous, then would it have been too light, which would 
have been very inconvenient. As to the fecond. the Weight is 
of confiderable Moment, for the more exaft Attrition of the 
Aliment, which is here requifite, becaufe tbe Tongue of this 
Animal is both (mail and polite on its Surface without thofe 
Iharp cartilaginous Papilla thole Animals are endued with, whofe 
Teeth are not fufficient to grind their Food. As to the third, l 
conceive that thefe hudimenta, with their intermediate Membranes, 
may be the more helpful to the Teeth in their Motion, if they 
have any, or Preffbre, than if the furrounding Jaw had been one 
whole continued folid Bone. For the fourth, a hard and foft Sub- 
fiance a ternatively plac d, is rtalniy more convenient for keep- 
ing any thing firm than either of the two alone ; for had they 
been hard Subftances that lay upon* one another, then neither 
'would yield to PrefTure*, and f foft, tho’ihey yielded, yet would 
they not fo well retain the Preffure they receive, and keep any 
thine firm thereby, as if they had fome intermediate Subfiance : 
In a°word, be the ufe of thefe Rudiment* what it will, the Teeih 
and they together have rendered this fo ponderous as to amount ;o 
4, tb Weight. And thus have we ended the External Farts of 
the Head. 
N. B. The remaining Part cf this Difconrfe (with tie Figures)' 
will be inferred in the- following TranlaCtion. 
