FIG. 138 



144 



Figs. 138-144. Mandibles of Arthrodirans : Cleveland Shale, Ohio. 138. 

 Mylostoma variabilts, Newb., visceral aspect. 139. Titanic lit hys clarki, Ne\vb., 

 visceral aspect. X \. 140. Trachosteus, Newb., outer aspect. >< J. 141. Diplo- 

 gnathus, Newb., outer aspect. < \. 142. Diplognathus, seen from dorsal side. 

 143. Diplflgiiathiis, visceral aspect. 144. Dniichthys intermedius, outer aspect. X \. 



137 



