36 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



course forward it joins the infraorbital canal on the jugal. The course of the infra- 

 orbital is not unusual in any respect. There is no anterior commissure on the skull, 

 nor is the occipital cross-commissure developed on either skull of the genus at hand. 



There are distinct evidences of an operculo-mandibular lateral-line canal on the 

 mandibles. The canal enters the mandible on the surangular and passes forward 

 around the mandible as described for Diplocaulus (477). 



Other members of the Stereospondylia, such as Mastodonsaurus, Metoposaurus, 

 and Trematosaurus possess well-developed lateral-line canals, but the above descrip- 

 tion fits, in a general way, the condition in all genera; and for our present purposes 

 that will suffice. 



