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. Agassiz 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. Agassiz 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, 



