in the Neighbourhood of Edinburgh. 205 
jaws, or the scales. To this information, which he promised to 
give me after he had instituted a comparison between the Mega- 
lichthys of Leeds and that of Burdiehouse, he has added an ac- 
count of other parts of the anatomy of the animal, the whole ha- 
ving reference to remarks made upon the recent Lepidosteus. 
M. Agassiz’s first observations were evidently directed to the 
dispelling of any possible doubt that the animal of Leeds was a 
sauroid fish. “ The head,” he observes, “is most perfect ; it is 
certainly that of a fish, since we see in it the opercular portions, 
and the branchiostic rays, which only subsist in this class of ani- 
mals; while behind are the scales of a portion of the trunk. It 
gives us, then, the greatest possible certainty with regard to the 
remains in question, as there are in the Leeds specimen many 
portions in an united state which are only found detached at 
Burdiehouse.” 
In reference to the same specimen, a comparison was made 
with minute bones obtained from Burdiehouse, evidently belong- 
ing to one of the fry of the Megalichthys, which had aided in the 
discovery, that the animal was less a perfect reptile than a sauroid: 
fish. M. Acasstz directs attention to the lamellar bone, which 
is represented in Plate IX. fig. 1, on the side where the indication, 
fig. 1, appears. He observes, that the lamellar bone, (plaque), 
here seen so distinctly, is the folium, which, in the head of Leeds, 
covers the space comprised between the branches of the inferior 
jaw, and which takes the place of the anterior branchiostic rays. 
On the opposite edge, as may be noted, is a row of maxillary 
teeth, alternately larger and smaller. 
The Structure of the Teeth.—With regard to the teeth of the 
Megalichthys, M. Acassiz states, that in the Leeds specimen 
they were small, but that upon one of them, which was broken, 
there was a striated surface characteristic of those of Burdiehouse. 
In comparing the teeth collected from Burdiehouse, with 
those of a specimen of the Lepidosteus, several feet in length, 
