126 



TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



Dapedius politus 



y>^ ^calebon&j 



LepidotusmantplU 



Fig. 22. Comparison of semionotid skulls of semi-orbicular type, (A) Dapedius, with more normal type (B), Lfpidolus. 

 In both the suspcnsorium is produced well forward. The postorbital row seems to have arisen through the down-growth and 

 budding of plate Y. The interopcrcular (absent as such in the pateoniscoids) has been derived from the produced lower end of 

 the subopercular (Tate Regan). 



