ITS STRUCTURE, BULK, AND ASPECT. 



dl 



ternal bones in my possession are curious, but exceedingly 

 puzzling. The bone a, fig. 45 (of which I possess two speci- 



Fig. 45. 



CLAVICLE AND LATERO-CEEEBRAL PLATE OF ASTEROLEPIS. 



(One-half nat. size.) 



mens, that, as indicated by their position in the rock, formed 

 parts of the same individual, occurring, the one in its right 

 side, the other in its left), apparently occupied the place in 

 the Asterolepis of that osseous st7/le which, in fishes such as 

 the haddock and cod, we find attached to the suite of shoulder- 

 bones, and which, according to Cuvier, is the analogue of the 

 coracoidian bone, and, according to Professor Owen, the ana- 

 logue of the clavicle. It curiously exemplifies how thoroughly 

 some of the bones in this ancient fish entered into the com- 

 position of at once the dermal and the internal skeleton ; for 

 while the tubercled portion of the upper part or head of the 

 style was unequivocally dermal, the lower or shank portion of 

 it, which must have traversed the muscles of the abdomen, 

 was, as shown by its channelled markings, as certainly inter- 

 nal. Of the bone 6, I only know that it belonged to the side 

 of the head.* Eig. c, 46, which is also a fragment, though a 



* In the earliest editions of this work, the place of the print fig. 45 

 was occupied by the subjoined wood-cut (fig. 47). I have since ascer- 



