OSTEOLOGY OF AMERICAN PERMIAN VERTEBRATES 407 



The coronoid reaches posteriorly on the upper side of the meckelian 

 orifice nearly to the anterior extremity of the articular; anteriorly 

 this bone borders the alveolar margin as far forward as the third 

 tooth. It is covered, for the most part, with small, conical teeth, 

 like those of the opposite palatal surface. These teeth had been 

 smoothly removed with the investing matrix in the first specimen 

 described, but their attachments are clearly visible under a hand- 

 lens; they are visible in the investing matrix of the second skull. 

 The splenial enters into the mandibular symphysis below, as 

 usual among the early vertebrates. The boundaries of the pre- 

 articular are less distinct posteriorly, though certain evidences 

 of sutural lines are visible as I have figured them. 



The teeth in the second specimen are somewhat better pre- 

 served than in the first; they are of somewhat larger size, but their 

 number and characters are quite the same. 



Any comparison of the skull of Casea with that of other reptiles 

 will be more or less speculative. It shares with Diadectes, Pantylus, 

 and Edaphosaurus the short, broad skull and more or less elevated 

 narial region. In all these the palatal region is practically closed 

 in front and covered with more or less thickly set teeth, indicating 

 similar food habits. From the nature of the obtuse mandibular 

 and maxillary teeth, I had inferred herbivorous habits; but it 

 is quite possible that the food may have consisted chiefly of the 

 softer invertebrates. Against this assumption, however, is the 

 very large abdominal capacity that suggests plant food. The 

 skull, as I have before suggested, has a strange resemblance to 

 that of Amblyrhynchus, the subaquatic Galapagos lizard, in the 

 great development of the narial region. 



The single large temporal vacuity reminds one of Edaphosaurus, 

 but the intimate resemblances end there. Nor is there a very 

 intimate relationship between Casea, the poliosaurids, as repre- 

 sented by Varanoops, or the ophiacodontids as represented by 

 Theropleura or Ophiacodon. That the genus represents a distinct 

 family there can be no doubt; its higher relationships must await 

 further discoveries — I have little faith in phylogenetic speculations 

 based on our present ignorance of the early reptilian faunas. 



