92 



THE ASTEROLEPIS, 



more considerable one, bears in its thickei and straighter edge 

 a groove like that of an ichthyodorulite, which, however, 



Fig. 46. 



c d c 



INTERNAL BONES OP ASTEROLEPIS. 



(One-third nat. size, linear.) 



the bone itself in no degree resembles. Fig. c? is a flat bone, 

 of a type common in the skeleton of fishes, but which in 



Fig. 47. tained, however, that the two fragments of 



bone which the latter presents belonged, not 

 to the Asterolepis, but to some large unnamed, 

 undescribed ganoid, its contemporary. The 

 bone a, similar in character and function to 

 the corresponding bone a in fig. 45, seems to 

 have been the clavicle of the imknown fish ; 

 while the bone b, — a mere fragment broken 

 at both ends, but exhibiting, in a state of good 

 keeping, lateral expansions like those of an 

 ancient halbert, — ^formed, in probably the 

 same animal, the analogue of part of that 

 <* ^ beam-like series of bones (consisting of the 



INTERNAL BONES OP ASTE- sub-occipital bone, the sphenoid bone, and the 

 EOLEPis. vomer) which compose in the ordinary fishes 



(One-half nat. size, linear.) the base of the skulL 



