432 MR. YOU ATT* S VETERINARY LECTURES. 
the powerful, yet minute and delicately-varied, action, to the 
muscles of the larynx which she has bestowed upon man; but in 
lieu of this he has given to almost all of them a conformation of 
the parts peculiar to each species, and pleasingly and usefully 
diversified the voice of each. 
Peculiarities in the Larynx of the Horse. —In the horse there 
is placed over the rima glottidis, at its anterior extremity, and 
reaching an eighth or tenth part from the point of the angle, as is 
shewn in this preparation, a delicate, but strong, and somewhat 
loose membrane, by the vibration of which the act of neighing is 
probably performed. There is also in the horse, as you perceive, 
a capacious membranous sac on each side of the larynx: the 
opening being about the centre of the vocal ligaments and imme¬ 
diately above them ; the sacs, taking a direction upwards and 
forwards, and capable of containing a small walnut, terminate in 
blind pouch. The precise connexion of this with the voice of 
the animal has never yet been satisfactorily explained. 
In the Ass there is a similar membrane over the anterior angle 
of the rima-glottidis, and there are also sacculi laryngis of the 
same character, but smaller, and placed nearer to the front of the 
larynx. 
The Mule possesses the larynx of his sire, and not of his dam. 
The Ox has neither a membrane across the rima glottidis, nor 
any sacculi laryngis. His voice is, of all our domestic qua¬ 
drupeds, that which is least capable of modulation. 
The Hog. —In this animal the aperture between the arytenoid 
cartilages is small ; the vocal ligaments take an oblique instead 
of straight direction across the larynx, so that the angle is at a 
considerable distance from the centre of the thyroid cartilage. 
They have also a curious slanting direction, the anterior angle 
being depressed, and the arytenoid portion elevated. There 
are also two sacculi, which seem to be concerned in the act of 
grunting. 
The Dog. —The larynx of the dog is most singular and com¬ 
plicated. There are two distinct sets of vocal ligaments, the 
one above the other; and there are also two lateral ventricles of 
considerable depth. These circumstances may account for the 
loudness and compass of voice in this animal. 
In the Cat the larynx is even more flexible than in the dog, 
and the rima glottidis more open; and there are two membranes, 
lying under the chordae vocales, which produce the purring noise 
made by this animal. 
