64 SKULL AND VISCERAL ARCHES IN LEPIDOSIREN AND PROTOPTERUS. 



ABBREVIATIONS USED IN THE TRANSPARENCIES. 



ant/., angular. 



d. ect., dermal ectethmoid. 



d. eth., dermal ethmoid. 



fen., fenestra. 



/.p., frontoparietal. 



int., interoperculum. 



op., operculum. 



p.-pt., palato-pterygoid bone. 



pal. t.p., palatine tooth-plates. 



par., parasphenoid. 



pi. occ, pleuro-occipital. 



pr. as., ascending process of palato-pterygoid. 



spl., splenial. 



sq., squamosal. 



vac, vacuity under hypophysis. 



vora. t., vomerine tooth. 



