Sir Everard Home on the milk tusks , &c. 14,5 
that form intermediate links in the chain of gradation between 
those that are already known. The truth of this observation 
is very strongly illustrated in the proteosaurus. 
Our knowledge of comparative anatomy has been so 
much encreased in extent within the last few years, that we 
can now better, than at any former period, attempt the ar- 
rangement of animals into a regular order, according to their 
internal mechanism ; showing that they form so many parts 
of one great system of structures ; and if the pursuit is fol- 
lowed with the same ardor, and attended with the like success, 
we may soon expect to have all the material links of this 
great chain made out. 
To assist our progress towards this end, the great purpose 
for which comparative anatomy is cultivated as a science, I 
have in all my researches into the structures of animals, or 
their fossil remains, kept it in view. 
The observations I now bring forward respecting the milk 
tusks, and organ of hearing of the dugong, have been made 
upon a skull of that extraordinary animal, in a very perfect 
state of preservation, sent to me, by my friend Sir Thomas 
Stamford Raffles, from Sumatra. 
There are three skulls which I may say have come under 
my observation, of animals nearly of the same age, but not 
entirely so, for although the milk tusks at their points in all 
of them, put on the same appearance, that is not the case with 
their other extremities. One of these skulls is in the posses- 
sion of M. Cuvier, and a figure of it is engraved in the thir- 
teenth volume of the Annales du Musee d’Histoire Naturelle ; 
and also in the fourth volume of his work, entitled Recherches 
sur les Ossimens Fossiles des Quadrupedts. In this figure the 
