234 
DBS. A. CABTE AND A. MACALISTER ON THE 
beneath this fold of mucous membrane there was a strong muscular band, the hyo-epi- 
glottideus muscle, which ran to the anterior surface of the epiglottis from the centre of 
the posterior aspect of the body of the os hyoides. A prominent ridge extended along 
the middle of the epiglottis on its posterior superior surface, descending into the larynx, 
becoming more prominent as it passed downwards, and ceasing at the insertion of its 
base into the thyroid cartilage. 
The anterior extremities of the arytenoid bodies were thick, fleshy, and somewhat 
tongue-shaped ; they were united to each other in the mesial line from the top of the 
cricoid cartilage to within 2 inches of their apices, where they separated and formed 
two free linguate extremities, whose inner surfaces were directed towards each other, 
and could be readily approximated by the contraction of the arytenoideus proprius 
muscle; their outer borders were thick and fleshy, and were continued down as promi- 
nent ridges into the larynx. 
There is an important difference existing between the glottis of Balcenoptera and that 
of Delphinus and Globioeephalus ; that the constituent parts of the free upward tubular 
prolongation of the larynx are closely united to a much greater extent in ’the latter 
animals, whereas in the former the lateral boundaries of this opening are quite separate, 
and only capable of being formed into a tubular elongation by the approximative action 
of their appropriate muscles. 
The cartilaginous portion of the epiglottis formed but a small part of the centre of 
the entire organ, and beneath its mucous investment its lateral parts were constituted 
of a layer of interlacing muscular fibres, which were continued into the loose fold of 
mucous membrane that enveloped the base of the arytenoid bodies. 
The larynx was firmly connected by muscles and ligaments to the os hyoides, which, 
as before described, consisted of a body and four cornua ; the former occupied the 
median space about 4 inches anterior to the thyroid cartilage ; its shape was that of a 
flattened triangle, whose rounded and emarginate apex was directed forwards, and whose 
lateral angles or posterior cornua were continuous with it, being prolonged backwards 
on each side. Its inferior surface was convex, and presented externally an oblique line 
that commenced about 2 inches from the apex and ran backwards and outwards to the 
tip of the external angle, to which was attached the mylohyoid muscle ; anteriorly there 
was a rough surface, about 2|- inches in extent, into which the basiokeratic muscle was 
inserted. The superior surface was concave, and was occupied in the middle line by the 
attachment of strong hyo-epiglottic ligaments and muscles ; external to these the deep- 
seated basiokeratic muscle had its origin, and extended outwards to the end of the 
external angle. The anterior border terminated in front in the apex, which latter was 
bounded on each side by a concave space, f to the anterior portion of which the bale of 
the anterior cornu or styloid bone was closely united by strong fibrous tissue, the 
remainder of the border being merely occupied by cellular membrane. The posterior 
margin was rounded and concave ; to it the sternohyoid and thyrohyoid muscles were 
attached, the former occupying a space extending outwards about 3 inches from the 
