104 THE ASTEROLEPIS, 



maxillary bones in the possession of Professor Asmus men 

 sures in length twenty-eight inches. And that space cii- 

 cumscribed by the sweep of the lower jaw, which it took, in 

 the Russian specimen, a hyoid plate twenty-four inches in 

 breadth to fill, could be filled in the two-and-a-half-feet cod 

 by a plate whose breadth equalled but an inch and a half. 

 Thus, in the not unimportant circumstance of size, the ancient 

 ganoids, instead of taking their places, agreeably to the de- 

 mands of the development hypothesis, among the sprats, 

 sticklebacks, and minnows of their class, took their place 

 among its huge basking sharks, gigantic sturgeons, and bulky 

 sword-fishes. They were giants, not dwarfs. 



But what of their organization 1 Were they fishes low or 

 high in the scale ] On this head we can, of course, deter- 

 mine merely by the analogies which their structure exhibits 

 to that of fishes of the existing period ; and these point in 

 three several directions ; — in two of the number, directly on 

 genera of the high ganoid order ; and in the third, on the 

 still higher placoids and enaliosaurs. No trace of vertebr89 

 has yet been found ; and so we infer — ^lodging, however, a 

 precautionary protest, as the evidence is purely negative, and 

 therefore in some degree inconclusive — that the vertebral co- 

 lumn of the Asterolepis was, like that of the sturgeon, carti- 

 laginous. Respecting its external covering, we positively 

 know, as has been already shown, that, like the Lepidosteus 

 of America and the Polypterus of the Nile, it was composed 

 of strong plates and scales of solid bone j and regarding its 

 dentition, that, as in these last genera, and even more de- 

 cidedly than in these, it was of the mixed ichthyic-reptilian 

 character, — an outer row of thickly-set fish teeth being back- 

 ed by an inner row of thinly-set reptile teeth. And its form 

 of coprolite indicates the spiral disposition of intestine com- 

 mon to the rays and sharks of the existing period, and of 

 the ichthyosauri of the Secondary ages. Instead of being, 



