( • >4 ) 
Jation, but that from the Right to the Left, they were wholly 
cavous : bach of them was inverted by a membranous Tunicle, 
as it were a Periofteum, and had fomething like a Cartilaginous 
Subftance betwixt the two. Their Surface is very unequal at the 
Orifice, where they receive the Ligaments and VelTels ( c.) and 
as if they had been folded into feveral plica, and afterward taken 
alunder, from which there run feveral Ridges and Sulci ( b. ) 
from one extremity to the other ; where the Ligaments ceafe,they 
become extreamly folid and ponderous, and at their upper Extre- 
mities half round, and fometimes form’d into Digitations (a.) 
Tab. 3. Fig. When they approach to that part of the Bone at which the Teeth 
appear, they begin to quit the Perioficum, by which they were 
diftinguifh d, and unite clofe together, fo as to form one Bone. 
’Tis o’olervable, that at their upper Extremity there is a Laming 
which being Convex toward the Jaw, and Concave toward thtfe 
Rudiments of leeth, do as it were knit their folid Extremities 
together, from which ’tis alfo fepa r ated by an intermediate 
Membrane at J the beginning j but afterward thatceafing, thisLa- 
mina conjoins them at the Extremities, as they are at the Sides, 
before they appear without the Jaw. And thus I conceive thefe 
Teeth to be form’d, and ’tis by thefe I am perfwaded the Jaw 
becomes fo ponderous and thick ; and that which ftrengthens this 
Opinion is, that the hind Teeth of both Jaws (for I doubt not 
but the'e Rudiment a Pentium are in the Upper Jaw alfoj before 
they come to grind, have their Upper Parts Semicircular 3 and 
that both before and after the Grinders are form’d, the Linea- 
ments of thefe Rudiment a appear plainly like fo many Ridges 
; (d.e) having intervening Furrows, where they formerly had 
Tig- 9 - been diftingujfhd by Membranes : And 1 fuppofe tho’ at the up. 
per Extremity they are united into one compact Bone, yet at 
their lower Extremity they have ftil! the fame Hollownelfes for 
Reception of the Ligaments and Veffels as formerly ; which Opi- 
nion is confirm’d by Tentaelwis Account. The Lower Jaw has 
4 Teeth, 2 on each fide ( d . e .) as well as the Upper, all Grind- 
ers, but no Incifors, or fore Teeth. The hind Teeth are 8 In- 
ches diftant, and the Fore not 4, betwixt which is plac’d the 
Sinus for the Tongue (d.e ) and ’tis obfervable, that from thence 
to the bottom the 'S>W is fo contracted, as only to be one Inch 
Tig - 7 8. broad (/. ) The hind Tooth- on the Right Side is 4 inches, on 
the Left 5. The one half of their Surface, where th&y begin to 
appear, is Semicircular, with the fore mention’d Ridges and Sulci 
running tranfverfely, 4 on the Right Side, and 5 on the Left. The 
other 
