CO CCO S TEOMORPHI 



263 



Family COCCOSTEIDAE. The preorbitals (frontals) meet behind the 

 pineal. The teeth are conical and of moderate size. The statement 

 that they extend on to the symphysis is probably erroneous (Jaekel 

 [244]). In some the ventral shield is produced at each side into a 

 process bearing a spine (Traquair [459]), which in others may be long 

 and movable (Fig. 231). 



Coccosteus, Ag., Brachydirus, v. Koen ; Devonian, Europe. Phlyc- 

 taenaspis, Traq. ; Devonian, Europe and N. America. Acanthaspis, 

 Pholidosteus, Jaekel ; Devonian, Europe. 



Family SELENOSTEIDAE. The mandibular bones bear a row of 

 conical teeth along the anterior and the symphysial edge (?). The cranial 

 shield has no orbital notches, and two 

 diverging posterior wings (Fig. 233). 



Selenosteus, Dean, Diplognathus, 

 Newb. ; Cleveland shale, N. America. 



Family DINICHTHYIDAE. With 

 three pairs of biting bony plates, on 

 the vomers, palatines, and splenials 

 with anterior beak -like processes 

 (Fig. 234). 



Dinichthys, Newb. ; Devonian, N. 

 America and Europe. 



T-. -i PTI IT Acanthaspis decipiens ; Devonian, Spitz- 



ramiiy UTAXICHTHYIDAE. Very bergen. Ventral view of body-shield, restored. 



large fish, with slender toothless jaws (After A. S. Woodward, Vert. Palaeontology.) 



' J ap, lateral spine ; pr, process supporting it. 



and very broad head. 



Titanichthys, Newb. ; Devonian, Carboniferous, N. America. 

 Family MYLOSTOMIDAE. The teeth are in the form of crushing 

 plates (Dean [108]). 



Mylostoma, Newb. ; Devonian, N. America (Fig. 233). 



Fio. 231. 



FIG. 282. 



Coccosteus decipien.i, Ag. ; Lower Old Red Sandstone. (After A. S. Woodward, 

 J!i it. Mint. Cittitl.) Left-side view, with dermal shields and endoskeleton. 



Sub-Order 2. TEMNOTHORACI. 



The very extensive and broad cranial shield is closely but 



movably joined to the trunk-armour. The orbits are surrounded 



by the post- and preorbitals ; the latter do not meet behind the 

 pineal (Fig. 235). 



Family HOMOSTEIDAE. Homosteus, Asmuss ; Devonian, Europe. 



