The Mermaid of Early Writers. 169 
- 6. In the Royal Society of Edinburgh there is deposited a cra- 
nium of a dugong, whose resemblance to that engraved in the Phil. 
Trans. 1620, Pl. 12, is so exact as to appear to be identical with it. 
The description given by Sir S. Rafiles, (vide p. 168, supra,) 
agrees minutely with the characters of the molar teeth in this spe- 
cimen. They are to the number of 12, three on each side of each 
jaw ; their surfaces are flat, approaching to a slight concavity: 
empty sockets indicate the previous existence of a greater number, 
which have been shed. 
The superior incisives, or tusks, are not advanced above half an 
inch out of the socket, having the points uneven and not at all 
worn. The extremity of the root has a cup-like concavity, as de- 
scribed by Sir E. Home, but there is no evidence of its ever hav- 
ing been separate from the rest of the tooth. 
. In the lower jaw there are four incisive sockets on each side, two 
of which contain rudimentary teeth, (as in Phil. Trans. 1620, Pl. 
14, Fig. 2,) directed into the substance of the bone; the others 
are devoid of teeth, and grown up with cancellations of bone.* 
- 7. In the Edinburgh College Museum, there is a handsome adult 
skeleton, nearly 8 feet long, which seems to be perfect except in 
the absence of the tympanic bone, .whose loss Dr. Knox ingenious- 
ly observed. Through the kindness of Mr. Frederick Knox, I am 
able to give the following description of the dentition of this ani- 
mal: -— 
On each side of each jaw there are three molar teeth, and other 
empty imperfect sockets, indicating the former presence of teeth 
which are gone. Their surfaces are quite smooth from use. 
Two incisores, or tusks, are deeply seated in the intermaxillary 
bones of the upper jaw, and diverge outwards when they project 
from the socket. The external surfaces of their extremities are 
worn flat by friction. Like the tooth figured in Phil. Trans. 1620, 
Pl. 13, Fig. 3, they are hollow to a considerable depth from the 
base. There are no incisives in the lower jaw, but there are five 
grown up sockets on each side. 
* Tt is the opinion of Dr. Knox, that “ the incisive teeth in the lower max- 
illary bone remain imbedded in their sockets throughout life; they are neither 
shed nor replaced. They seem to be eight in number.” (Brewster’s Journ. 
N.S. Vol. [. P. 157.) It must, however, be remarked, that in the adult spe- 
cimen in the College Museum, the inferior incisive alveoli ave all grown up, 
and though they present evidences of being formerly occupied, no teeth remain 
in them now. 
+ At the time that this paper was already in the press, and it only remained 
for me to corroborate by minute examination the notes which had passed 
through the hands of Mr. Knox, who articulated this skeleton, I requested 
the Professor of Natural History, who is also Keeper of the Museum in this 
University, to permit me to have access to the collection for this express pur- 
pose ; and, indeed, as I was aware that a degree of jealousy was attached to 
the admission of those who might employ the valuable materials which lie on 
those shelves “ unnoticed and unknown,” I provided myself with a ticket to 
the ensuing winter’s course of Natural History, for the sole purpose of secur- 
ing that favour, which had been promised to me before the delivery of the 
fee. But I have since been prevented from performing the duty to the pub- 
lic which I imposed upon myself when I undertook to write upon this supject, 
YOL,. I, Y 
