BRANCHIOSTEGiL RafS 



Fig. 316. Developmental stages of neurocranium of the bowfin, Amia calva. (A and 

 B redrawn from De Beer, '37, after Pehrson; C and D from Allis, 1897, J. Morph., 

 12.) (A) Ventral view of 9.5-mm. stage. (B) Dorsal view of 19.5-mm. stage. (C) 

 Cartilaginous neurocranium of adult stage. (D) Dermal (membrane) bones overlying 

 neurocranium of adult stage. Cartilage = coarse stipple; bone = fine stipple. 



670 



