ANATOMY OE B ALiEN OPTEEA EOSTEATA. 
233 
described. This space was deeply alveolated, and its mucous surface presented a reti- 
culated appearance, somewhat resembling the carneee columnse of the heart ; its central 
portion, however, for about the width of 1^ inch was smooth, being perfectly free from 
all such alveolations. Posteriorly and laterally the alveoli were arranged in five or six 
transverse series, gradually diminishing in size until they entirely disappeared towards 
the middle of the pharynx, where the mucous membrane became perfectly smooth, and 
so continued until it reached the commencement of the oesophagus. 
Two inches in front of the root of the epiglottis, and surrounded by the alveolated surface 
just described, there was a strong crescentic hood-like fold of mucous membrane, the 
concavity of which was directed backwards ; this fold measured along its free posterior 
border 9 inches, and the lateral cornua of this edge were prolonged on each side of the 
opening of the glottis in the form of frsena, which were gradually lost in the mucous 
membrane of the upper part of the oesophagus ; its convex margin anteriorly was con- 
tinuous with the before-mentioned alveolated space ; the depth of the fold at its central 
part, which corresponded to the opening of the larynx, was about inches ; its inferior 
surface was smoother than its superior, and was studded with the orifices of numerous 
minute mucous pores. This hood-like fold formed the covering of a cavity capable of 
containing half a large orange. Beneath the mucous membrane of this fold were curved 
muscular fibres passing from side to side, whose use appeared to be for the contraction 
of the subjacent pouch. 
This remarkable hood-like fold was capable of being drawn over the orifice of the 
glottis when the margins of that opening were approximated, and its use appeared to 
be to cover and protect the superior opening of the larynx during the act of deglutition, 
a purpose which could be completely accomplished by the contraction of the muscular 
fibres between its laminae, which, when the arytenoid bodies and epiglottis were closely 
approximated, would suffice to cover and keep together the sides of the opening. 
Immediately posterior to the crescentic or hood-like fold was placed the upper opening 
of the larynx or glottis, on each side of which was situated a deep channel, which was 
directed backwards and downwards towards the oesophagus, being separated only from 
the glottis by that portion of the mucous membrane which was prominently elevated 
on each side to form the aryteno-epiglottidean folds. Numerous rugae and mucous 
pores were situated on the outer wall of this channel and continued down to the oeso- 
phagus. 
The orifice of the glottis was triangular in outline, the base being placed at the epi- 
glottis, and the apex between the arytenoid bodies, the lateral boundaries being formed 
by the aryteno-epiglottidean folds. 
The epiglottis was tongue-shaped and extremely flexible ; its base was attached pos- 
teriorly to the central part of the upper surface of the thyroid cartilage, and its edges 
laterally became continuous with the aryteno-epiglottidean folds which embraced the 
bases of the arytenoid bodies. It was attached anteriorly in the median line by a well- 
developed ficenum, which extended into the floor of the pouch or sac before noticed ; and 
mdccclxviii. 2 L 
