OF THE EARLIER VERTEBRATA. 



47 



pies its proper place, joins posteriorly to a little plate, a, im- 

 perfectly separated in most specimens from the parietal, but 

 which seems to represent the par-occipital bone ; and it is a 

 curious circumstance, that as, in many of the osseous fishes, 

 it is to these bones that the forks of the scapular arch are at- 

 tached, they unite in the Coccosteus in furnishing, in like man- 

 ner, a point of attachment to the cuirass which covered the 

 upper part of the creature's body. Of the true internal skull 

 of the Coccosteus there remains not a vestige. Like that of 

 the sturgeon, it must have been a perishable, cartilaginous 

 box. 



In the Osteolepis, — an animal the whole of whose external 

 head I have, at an expense of some labour, and from the exa- 

 mination of many specimens, been enabled to restore, — the 

 cranial buckler (fig. 1 2) was divided in a more arbitrary style ; 



CRANIAL BUCKLER OF 0STE0LEPI3. 



and we find that an element of uncertainty mingles with our 

 inferences regarding it, from the circumstance that some of 

 its lines of division, especially in the frontal half (C), were not 



