354 



PALAEONTOLOGY OF OHIO. 



STEGOCEPHALI. 



The cranial elements distinct, including frontals and pterygoids, and 

 adding " postorbitals and supratemporals," a supraoccipital and an epi- 

 otic; quadrate osseous, frequently (? always) supporting a squamosal; 

 caudal vertebrae distinct; orbitosphenoids normal, ? ethmoid; inferior 

 pelvic elements distinct; mandible dentigerous; teeth with anchylosed 

 bases, or in shallow alveoli; proximate tarsals not elongate. (A quad- 

 rato-jugal. 



Fig. 2. 



Fig. 3. 



Figs. 2, 3, and 4, Rana Oatesbyana. — Fig. 2, side view of oraninm ; 3, the same, with squamosal, pre- 

 : frontal, malar, aod quadrato-jugal bones removed. Fig. 4, posterior view of the cranium — references aa in 

 ' fig. 1 ; -FP, frontopailetal bone ; F, vomer ; PiS, parasplienoid j A, angular ; 0, coronoid ; D, dentary. 



ANUEA. 



Frontal and parietal confluent, nasals wanting or rudimental ; no epiotic 

 nor supraoccipital ; postorbital and supratemporal wanting; quadratum 

 cartilaginous, covered by squamosal ; ethmoid, an annulus (usually com- 

 plete above) surrounding cerebral lobes; caudal vertebrae represented by 

 .an elongate, originally compound style; inferior elements of the pelvis 



