CO CCOSTEOMORPHI 



265 



Outer view of right jaws of Dinichthysintermedius,'Sevf\).; Upper Devonian, Ohio, a, anterior 

 upper piercing plate ; md, lower piercing and cutting plate ; p, posterior cutting plate ; so, sub- 

 orbital, showing lateral-line groove. (From Brit. Mus. Guide.) 



Homosteus milleri, Traq. Cranial and dorsal shields, etc., restored. (After Traquair, from 

 A. S. Woodward.) A, B, C, undetermined bones; a.dl, anterior dorso-lateral ; ae, ethmoid ; 

 c, central; e.o, external occipital; m, marginal ; m.d, median dorsal; m.o, median occipital; 

 0, orbit ; p.dl, posterior dorso-lateral ; po, preorbital ; pte, pineal ; pto, postorbital. Double 

 dotted lines indicate the course of lateral-line canals. 



