Ixxiii 
fold of membrane, of the same colour and texture ; from its 
centre is a short, conical projection, analogous in its position, 
in front of the glottis, to an epiglottis, and capable of acting 
as such to a slight extent ; it is devoid of cartilage, but when 
the tongue is retracted, this process can cover the anterior 
half of the glottis. The Hyorp Bong, or rather cartilage, 
supports the tongue by a broad basis, from the centre of 
which a short, strong style passes forwards in the median 
line; a similar process descends in front of the thyroid carti- 
lage, and is attached to it, and to the forepart of the trachea, 
by elastic ligament; the cornua are pliant and elastic, and 
curved backwards in a tortuous form; they support the pha- 
rynx and fauces, and admit of considerable expansion. The 
glottis, or superior larynx is well developed, and bears some 
resemblance to the rima in mammalia ; its aspect is obliquely 
upwards and backwards, and is placed, as usual in birds, on 
the posterior plane of the trachea, though not to the same 
extent; but it is devoid of all spines, tubercles, and papilla, 
nor has it the chink-like form so common in that class. The 
thyroid cartilage bounds the larynx in front, the cricoid be- 
hind: on the upper edge of the latter are two thin broad plates, 
passing forwards, from the inner side of the centre of each 
there is a prominent and firm fibro-mucous body, projecting 
inwards ; these bodies bear some analogy to arytenoid carti- 
lages ; they nearly touch, and can easily be made to do so, 
whereby the opening is divided into two parts; the anterior, 
small and triangular, can be covered by the epiglottis when 
the tongue is retracted; the posterior is round or oyal, and 
can only be closed by the action of the surrounding muscles 
pressing its sides into contact during the act of deglutition. 
These two portions bear a close resemblance in form to the 
human rima glottidis, when subdivided into two by the approxi- 
mation of the long, anterior, basilar processes of the arytenoid 
cartilages (fig. 1) ; 
The trachea is of considerable length, the rings are all 
