43B ME M O IR S of the 
which is the bafis of the Nucleus Tyramiddls of the Cochlea, 
feveral fibrils, which as foon as they enter the Cochlea^ accom- 
panied with their Imall arteries and veins, do there change 
their form, and are difpofed and diftributed in the following 
manner 5 and firft, that thin membrane, which they receive 
from the Tia Mdter, fpreads itfelf in fuch a manner, as to 
terminate in a very fine fmall membrane furnin^icd with innu- 
merable blood-ve&ls, which at firft lines the fuperficies of the 
bafe of the Nucleus ^yramidalisG^ the Cochlea, and all it con- 
tains, as far as the fecond winding of the fpiral Lamina of the 
faid Nucleus-, afterwards it extends into the femi-oval fpiral 
du6^ of the Cochlea, and is fo expanded, as to iliut up its extre- 
mity, and line all its fuperficies 9 as alfo, both fides of the femi- 
oval fpiral Lamina which lies therein 5 and this membrane as 
being of a very fine and curious texture, does not hinder the 
continual and quick paffage of the ethereal matter out of the 
tympanum into the labyrinth and all its receffes 3 hence it is, 
that it wasfaid above to enter into the labyrinth itfelf, thro' a 
cavity fituated behind its Janua: As to the medullary fubftance 
of the nervous fibrils, one portion thereof is fpent in forming 
the fecond winding of the fpiral Lamina, which furrounds the 
Nucleus 'Pyramidalis of the Cochlea, the internal (ide of which 
winding is entirely bony, as was abovementioned j the other 
portion does at firil form the beginning of the fame Lamina^ 
which only confifls of half a winding, and is entirely nervous, 
and then extending to the femi-oval fpiral du6l o£thcCcchka, 
it terminates in a nervous femi-oval fpiral Lamina, which is 
fituated there, and which by its thick part adheres to the bony 
line of this dufl, fo that the beginning of the fpiral L.amina of 
the Nucleus Tyramidalis of the Cochlea is alfo that of the femi- 
oval fpiral Lamina, juft now defcribed 5 which laft, extending 
to the extremity of the femi-oval fpiral duct wherein it lies, 
adheres by its fharp extremity to the middle of the fmall 
chink in the bafe of the Concha, and fo divides that dudl into 
two parts, between which there is no vifible communication ; 
and thele two parts are difpofed in fuch a manner, that the 
firll, which regards the interior parts of the head, communi- 
cates with the Vefiihulum primum £i? fecundwn of the laby- 
rinth 5 but the fecond, which regards the Tympanum, and con- 
feqnently, the external parts of the head has a communication 
with the Concha only : The middle ramification of the ^ortio 
Mollis, or foft branch of the feventh pair of nerves, after it 
fends out the fmall fibrils already defcribed, enters a fmall 
Foramen 
