166 On the Natural History of the Dugong, 
But in the dental characters of these animals, and the develope- 
ment of bones connected with the teeth, we observe the most strik- 
ing differences. Sutflice it to say, that the dugong possesses large 
tusks in the intermaxillary bones, which are of enormous size, 
whilst, except in its early youth, the manatee has none. Indeed, 
_Cuvier remarks “ that the manatee may be said to be a dugong 
whose tusks are not developed.” * 
From the consideration of the teeth of the dugong brought from 
the East Indies, and from a belief which obtains amongst the Ma- 
lays, countenanced by a comparison of the cranium figured b 
Daubenton, with the specimens brought home from the East Indies 
by MM. Diard and Duvaucel, it has been conjectured that there 
may probably be two species or varieties of this animal. And in 
No. I. of the New Series of Brewster’s Journal, Dr. Knox pub= 
lished the results of some inquiries, which led him to suppose it 
“ not unlikely that the differences in the form of the tusks, may 
originate not in a difference of age, but in their belonging to dis- 
tinct varieties or species of the dugong,” (p. 158.) 
Since the publication of this notice, Dr. Knox, whose experience 
and zeal as a comparative anatomist are more generally known than 
his disinterested participation of the knowledge he possesses, has 
paid me the compliment. of calling my attention to this question ; 
and I have collated the evidence afforded by the writings of others, 
and compared it with the two specimens deposited in the collection 
of the Royal Society, and in the museum of the College, in this 
city, with the view of determining the nature of those differences 
which we have observed. 
_ As it is not in my power to enter upon a minute examination of 
the skeleton of the dugong, and as the principal distinctive charac- 
ters are derived from the teeth, I have confined myself to an inves- 
tigation into the peculiarities of these organs, as observed in diffe- 
rent specimens, the comparative size of whose crania is given. 
The data (consisting of descriptions and engravings of crania, 
and of osteological preparations in the museums of this city) are 
perhaps sufliciently numerous for accurate deductions ; but it would 
have been highly valuable had the history of the specimens been’ 
more complete. 
They are, 1st, The figure and description of a mutilated cranium, 
engraved by Daubenton, (Tom. xxvii. P. 289, Pl. 56. Paris 
1766 ;) and, after him, by Cuvier, (Oss. Foss. Tom. v. PI. 19.) 
2d, The description, by Camper, of a cranium so very similar to 
are totally different, which shows the mode of classing animals from the ap- 
ELIS of the teeth, to be very erroneous,” (Phil. Trans. 1821, p. 391.) 
fn the first edition of his great work, published in 1816, Cuvier adopted the 
generic separation between the manatee and the dugong, which had been esta- 
Dlished by Lacepede. But the knowledge of species was of secondary impor- 
en whilst every fresh arrival crowded the museums with ad captandum no- 
velties. 
* Ossemens Fossiles, V. 260. 
