PTERICHTH YOMORPHI 



209 



Cephalaspidomorphi. Especially important is the position and 

 structure of the orbits so peculiar amongst Pisces, and so essentially 

 similar in both cases. The pectoral appendages may, moreover, 

 be compared with the paired flaps of Cephalaspis, also covered with 

 dermal armour. 



cf 



nv. 



Fia. 1SU. 



s ; restored. (After Patten.) c, cephalic shield ; cf, ventral lobe of caudal tin ; 

 c.v, dorsal lobe of caudal fin ; d./, second dorsal fin ; e, eye ; m, mouth ; p, pectoral jointed 

 appendage ; .-/(?, fold of skin (pelvic tin ?) ; t.x, thoracic shield. 



Family ASTEROLEPIDAE. Asterolepis, Eich. ; Pterichthys, Ag. ; Micro- 

 Irachius, Traq. ; Devonian, Europe. Hothriolepis, Eich. ; Devonian, Europe 

 and Canada. 



