Explanation of Plate XII 



Restoration of the jaw muscles of Eryopz, representing the Temnospondyli, and 



of Labidosaurus, representing the Cotylosauria 



Fig. 1. — Enjoys. Superficial muscles. 



Very probably the jaw muscles of this form were fundamentally similar to 

 those of modern amphibians and include superficial, middle and deep layers <>i 

 the capiti-mandibularis (Cm.). The pterygoideus anterior (Pt. ant.) very 

 probably had the normal course and crossed the capiti-mandibularis on the 

 inner side. The jaw was doubtless depressed by the depressor mandibula? 

 (D.m.) lying behind the quadrate. 



Figs. 2-4. — Labidosaurus. 



As in the Temnospondyli (Fig. 1) the jaw muscles were entirely beneath the 

 dermal skull roof. The capiti-mandibularis was probably differentiated into 

 three layers and was inserted into the Meckelian fossa of the mandible, and 

 the pterygoideus anterior probably crossed beneath these, being inserted on the 

 hack of the mandible. 



ang, = angular d. — dentary 



art. = articular pa. =zprearticular 



cor. = coronoid sp. = splenial 



