254 



THE CARBONIFEROUS SYSTEM. 



Fig. 77 .—Placoid and Ganoid Fishes from the Lower Carboniferous.— Horton Bluff". 



(a, I, c, d) Portion of Jaw, Tooth, and Scales of Rhizodus Hardingi, Dawson— nat. size. The 

 tooth (b) is a little too slender. 



(e,/) Portion of Jaw and Scale of Acrolepis Hortonensis, Dawson— the scale magnified. 

 (g, A) Spine of Ctenacanthus and portion magnified. 



