FAUNA OF THE CARBONIFEROUS AGE. 



\, : 



Fig. 576. 



Fig. 575. 



Figs. 571-576. —Carboniferous Fishes— Placoids • 571. Cochliodus contortus. 572. Petalodus 

 destructor (after Newberry). 573. Cladodus spinosus (after Newberry). 574. Orodus mammi- 

 lare (after Newberry). — Ganoids; 575. Amblypterus macropterus. 576. Tooth of Holoptychius 

 Hibberti, natural size. 



still the rulers of the seas. Of Placoids, one has been found with dorsal 

 spine eighteen inches long, another with spine three inches broad and 

 nine and a half inches long, although much of the point is broken off. 

 Their teeth, too, are beginning to assume more of the character of true 

 shark's-teeth. They are no longer wholly Cestracionts (Fig. 571), but 

 also now Tlybodonts, having teeth somewhat like modern sharks, but 

 rounded on the edges (Figs. 573 and 574). Among Ganoids, the 

 well-protected but sluggishly-moving Placoderms have passed away, 

 but the Sauroids continue in increased numbers and size. Bony, en- 

 ameled scales of the Megalichthys and Holoptychius are found, two to 

 three inches across; and jaws of the Holoptychius, a foot or more 

 long, armed with Saurian teeth, two inches in length (Fig. 576). Also, 



