Explanation of Plate XI 



Partial reconstruction of the jaw muscles of Dinichthys, representing the 



Arthrodira 



Fig. 1. — Dinichthys. 



Jaws closed, depressor capitis (D.c.) contracted, levator capitis (L. c.) ex- 

 tended. 



Fig. 2. — Dinichthys. 

 Jaws open, depressor capitis extended, levator capitis contracted. 



