24 THE RECENT HISTORY 



those of the Iloloptychlus. And the stellate markings which 

 M. Eichwald graphically describes as minute paps rising out 

 of the middle of star-like wreaths of little leaflets, were re- 

 stricted to the dermal plates of the head. 



Agassiz ultimately succeeded in classing the bones which 

 had at first so puzzled him into two divisions, — interior and 

 dermal ; and the latter he divided yet further, though not 

 without first lodging a precautionary protest, founded on the 

 extreme obscurity of the subject, into cranial and opercular. 

 Of the interior bones he specified two, — a super-scapular bone 

 (supra-scapulaire), — that bone which in osseous fishes com- 

 pletes the scapular arch or belt, by uniting the scapula to the 

 cranium ; and a maxillary or upper jaw-bone. But his world- 

 wide acquaintance with existing fishes could lend him no as- 

 sistance in determining the places of the dermal bones : they 

 formed the mere fragments of a broken puzzle, of which the 

 key was lost. Even in their detached and irreducible state, 

 however, he succeeded in basing upon them several shrewd 

 deductions. He inferred, in the first place, that the Astero- 

 lepis was not, as had been at first supposed, a cuirassed fish, 

 which took its place among the Cephalaspians, but a strongly- 

 helmed fish of that Celacanth family to which the Holopty- 

 chius and Glyptolepis belong ; in the second, that, like seve- 

 ral of its bulkier congeners, it was in all probability a broad, 

 flat-headed animal ; and, in the third, that as its remains are 

 found associated in the Russian beds with numerous detached 

 teeth of large size, — the boar-tusks of Kutorga, — which pre- 

 sent internally that peculiar microscopic character on which 

 Professor Owen has erected his Dendrodic or tree-toothed 

 family of fishes, — it would in all likelihood be found that both 

 bones and teeth belonged to the same group. " It appeal's 

 more than probable," he said, " that one day, by the discovery 

 of a head or an entire jaw, it will be shown that the genera 

 Dendrodus and Aaterolepis form but one." As we proceed, 



