132 



AR THR ODIRAN L UNG-FISHES 



an analogy afterward supported by Newberry, Dean, and 

 recently, on account of the similar characters of the sen- 

 sory canals, by Pollard. In their conclusions, however, 

 fundamental characters of structure seem to have been 

 overlooked in the unlikeness of Arthrodiran to Tele- 

 ostome. The inner structure of the cranium of Arthro- 



PM 



PO 



FIG. 131 



Figs. 131, 132. Coccosteus decipiens. Dorsal view of dermal armouring. X J. 

 (After TRAQUAI-R.) 132. Ventral plates. (After TRAQUAIR.) 



ADL. Antero-dorso-lateral. AL. Anterolateral. A VM. Antero-ventro-lateral. 

 C. Central. E. Ethmoid. EO. Epiotic. IL. Inferior lateral. M. Marginal. 

 MC. Mucous canals. MD. Median dorsal. MO. Median occipital. MV. Me- 

 dian ventral. O. Opercular. PDL. Postero-dorso-lateral. PL. Posterior lateral. 

 PM< Premaxillary. PN. Pineal. PO. Preorbital. PTO. Postorbital. PVL. 

 Postero-ventro-lateral. SO. Suborbital. 



dira was evidently entirely cartilaginous ; in a Russian 

 Coccosteid, according to Smith Woodward, the base of the 

 brain case (parachordal cartilages) has been preserved and 

 shows a " tubular canal originally occupied by the anterior 



