the anatomy of the dugong. 319 
The spleen is made up of a fine beautiful reticulated net- 
work. 
The external opening of the nose is that of the whale 
tribe in miniature ; and the os hyoides has the same form as 
in that tribe. The epiglottis is long, and has a ligamen- 
tous edge ; it stands up in the posterior nostrils, but does 
not form a tube with the glottis, as in the whale tribe. 
The glottis is very similar to the human, as well as the 
thyroide, cricoide, and arytsenoide cartilages. There are no 
sacculi laryngcei ; but two ligaments pass forwards from the 
base of the arytasnoide cartilages to have an attachment to 
the concave surface of the thyroide, forming a rimula glot- 
tidis, which can be made wider and narrower, and the liga- 
mentous bands tighter or looser, by the action of the arytae- 
noide muscles. I have dwelt more upon the cartilages of 
the larynx, which are so different from those of the whale 
tribe, as this animal is said to be capable of making a noise 
not unlike the cry of a young child. The trachea is only 
two inches long before it divides into two ; the rings are 
circular, although not regularly separate from each other. 
The lungs in the larger dugong are two feet in length, 
that is one-fourth the length of the animal ; they are ex- 
ceedingly elastic, and the cells are very small, about the 
same size as in the whale : those nearest the surface are 
twice as large as the others, so that they cannot readily 
empty themselves entirely. The rings of the bronchias are 
very strong ; they are oval in their form, and run into one an- 
other. This circumstance is shown in Plate XXIX. 
The greatest peculiarity in the structure of this animal, is 
that of the ventricles of the heart being completely detached 
