OF THE EARLIER VERTEBRATA. 53 



it wore almost all its bone outside, as naked as tlie human 

 tPetA. 



Tbe cranial buckler of the Diplopterus (fig. 1 6) somewhat 



Fig. 16. 



CRANIAL BUCKLEB OF DIPLOPTERUS. 



resembled that of its fellow-dipterian the Osteolepis, but ex- 

 hibited greater elegance of outline. My first perfect speci- 

 men, which I owe to the kindness of Mr John Miller of 

 Thurso, an intelligent geologist of the north, reminded me, 

 as it glittered in jet-black enamel on its ground of pale gray, 

 of those Roman cuirasses which one sees in old prints, im- 

 paled on stakes, as the central objects in warlike trophies 

 formed of spoils taken in battle. The rounded snout repre- 

 sented the chest and shoulders, the middle portion the waist, 

 and the expansion at the nape the piece of dress attached, 

 which, like the Highland kilt, fell adown the thighs. The 

 addition of a fragment of a sleeve, suspended a little over the 

 eye-orbits, 2, 2, seemed all that was necessary in order to 

 render the resemblance complete. But as I disinterred the 

 buried edges of the specimen with a graver, the form, though 

 it grew still more elegant, became less that of the ancient 

 coat of armour : the snout expanded into a semicircle j the 

 eye-orbits gradually deepened ; and the entire fossil became 

 not particularly like anything but the thing it once was, — ■ 

 ine cranial buckler of the Diplopterus. The print (fig. 17) 



