CHAPTER I. 
And oppofite to this a thin one which in part divides the nofe. The 
greater part of the lamina: fpongiofse in the nofe belong to this bone. 
(Tab. v. vii. viii.) 
Os fphcnoidcs, (Tab. iv. v. vi. vii. viii.) is of a very irregular figure; it 
is feated in the middle of the bails of the fcull, bounded by the os fron¬ 
ds, ethmoidcs, vomer, occipitis, maxi lice fuperioris, ofla parietalia, palati, 
malarum, temporum, and petrofa, which arc parts of the former bones. 
In its iniide next the brain is a cavity named fella turcica, which is 
bounded by four procefles called clinoides; under the two foremoil of 
which pafs the internal carotid arteries, and from their outfides are con¬ 
tinued two thin long procefles upon that part of the frontal bone, which 
feparates the anterior lobes of the brain from the pofterior; oppofite to 
the fella turcica is a procefs which makes part of the feptum narium. On 
the outfide of the fcull adjoining to the upper jaw, are two proceiles of 
this bone on each fide, named pterygoides, from which arife one on each 
fide near the palate, which have no name; over thefe pafs the tendons 
of the ptcrygoftaphylini externi mufcles; and nearer towards the oc¬ 
ciput, between thefe and the ftyloid proceiles of the ofla petrofa, ariie 
two more fmall rugged procefles; and under the fella turcica, in this bone, 
is a finus or two, for the moil part, in adults, but in children only fuch a 
fpongy fubflance as is feen in the ends of feme of the bones. At the iniide 
of the bails of the two anterior clinoid procefles are two round holes, 
which are the firft foramina of the fcull; through thefe the optick nerves 
pafs; almoft under thefe, towards the fides of the fcull, arc two irregular 
ilits named foramina lacera, or the fecond foramina of the fcull, through 
which pafs nerves and blood-veflels into the orbits of the eyes ; and un¬ 
der thefe, towards the occiput are two round holes, which are the third fo¬ 
ramina, through which pafs nerves to the face; about halt an inch nearer 
the occiput are two more of an oval figure, which arc the fourth fora¬ 
mina, through which pafs the largeft branches of the fifth pair of nerves; 
and a ftraw’s breadth farther two very fmall ones called the fifth forami¬ 
na, through which thofe branches of the carotid arteries enter that arc be¬ 
llowed upon the dura mater. Between this laft deferibed bone and the of- 
fa petrofa are two large rough holes, in which I have feen large veins; and 
from thefe holes, through part of the os fphcnoidcs, under the pterygoid 
procefles, are fmall holes, through which pafs arteries to the back part of 
the nofe. 
Ofla temporum, (Tab. iii. iv. v. vi. vii.) are fituated below the parietal 
bones, at the middle and lower parts of the tides of the fcull; they have 
