HIGHER CHORDATES 



269 



dorsal spine 



branchial opening 



endolymphatic pore 

 dorsal field 

 eye_ 



"■lateral fields 

 nasohypophyseal opening 



TREMATASPIS 



lateral field 



cornual process- 



CEPHALASPID ""pectoral paddle 



PTERASPID 



LASANIUS 



Figure 16.2 Restorations of some ancient ostracoderms and their relatives. (From Chordaie Mor- 

 phology by Malcolm Jollie. N. Y.: Reinhold Publishing Corp., 1 962.) 



COCCOSTEUS 



GEMUNDINA 



BOTHRIOLEPIS 



Figure 16.3 Restorations of some fossil placoderms. (From Malcolm Jollie, Chordaie Morphology, 

 Reinhold Publishing Corp., New York, 1962.) 



