598 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
form the floor of the cavity (these have been described along with the organs of voice) ; 
but on either side of them are several longitudinal elastic folds of membrane (aryteno- 
epiglottidean folds) connecting the root of the epiglottis with the wavy plications of 
the cesophageal portion of the pharynx. 
Inferior constrictor.—Under this head I shall describe what represents the above in 
human anatomy ; but here it may conveniently be subdivided into two portions, although 
the fibres of these in the median line closely intermingle with one another. 1. The 
crico-pharyngeal portion springs as a narrow strong muscular band from the posterior 
hinder (inferior) angle of the cricoid cartilage, close to and somewhat overlapping the 
margin of the crico-thyroid muscle. Its fibres curve slightly forwards and round the 
cesophagus, mingling, as already hinted, with the second portion, 2. The thyro- 
pharyngeal portion is much the broader, and consequently stronger, of the two. Its 
origin is from the surface of the thyroid cartilage between its oblique line and upper 
posterior cesophageal border; whence the fibres are directed in an arched manner, 
meeting their fellows from the opposite side, and with scarcely any median fibrous 
raphe. The anterior median fibres curve in an angular manner forwards, considerably 
overlapping those of the middle constrictor. 
Middle constrictor.—Like the last, this is an expanded, tolerably thick, fleshy 
layer, the fibres of which are coarse and present clefts such as might suggest separa- 
tion of portions, as in the preceding; moreover its points of attachment are more 
numerous than in that muscle. Its most posterior origin is a superficial slip which 
overlaps the thyro-hyoid muscle. Fibres joining this slip come deeply from the thyro- 
hyoid ligament immediately adjoining the superior laryngeal nerve; this portion arches 
towards the middle line. The broader portion in advance of this arises from the thyro- 
hyal nearly its whole length. This attachment has fibres in conjunction with the 
thyro-hyoid muscle which it overlaps; in the same way it overrides and commingles 
with the origin of the hyoglossus, and in turn itself is overlapped by the outwardly 
expanded posterior fibres of the genio-hyoid, which, indeed, intimately mix with it. 
On the right side a further narrow slip arose from the thyrohyal. From these several 
sources the fibres proceed round to meet their fellows of the opposite side. Posteriorly 
they are arched considerably, so that part of the muscle passes under the inferior 
constrictor, the hinder border being convex. About the middle they are nearly 
transverse, and in front present a concavity forwards, the centre being attached to 
the skull. 
The superior constrictor underlies the fore part of the latter muscle, and is altogether 
very much weaker. 
3. Alimentary Canal. 
a. Relative positions of the Abdominal Viscera.—A longitudinal median incision having 
been made into the abdomen from the ensiform cartilage to the pubis, the contained 
viscera were found disposed in the undernoted condition. The Liver, which occupies 
