ORDER I 



STEGOCEPHALIA 



131 



chis, Dissorophus, Acheloma, Anisodexis, Cope. Permian ; Texas and Xew 

 Mexico. 



Erijops, Cope {Bhachitomus, Epicordylus, Parioxys, Cope), (Fig. 219). Largest 

 of North American Stegocephalians. Skull 40-60 cm. long, and 30-46 cm. 

 wide at occiput, elongated triangular, with somewhat tapering snout. Orbits 

 round, relatively small, placed in hinder half of the skull. Anterior nares 

 large, widely separated. Cranial bones rugose, sutures indistinct. Para- 

 sphenoid very thick, dagger-shaped. On the palatine two large conical teeth. 

 Maxilla and premaxilla with teeth of 

 various sizes. Teeth sharply conical, on 

 the top smooth, at the base ribbed. 

 Vertebrae rhachitomous. Caudal vertebrae 

 few in number, the posterior ones fused 

 into a triangular piece, tapering acutely 

 behind. Eibs strong, those of the sacrum 

 very broad and short. Permian ; Texas 

 and New Mexico. 



Cricotus, Cope. Total length, 3 m. 

 General form elongate, with triangular 

 skull and short, stout limbs. Snout 

 narrow, orbits large, elongated oval, 

 situated near the middle of the skull. 

 External bones faintly sculptured, sensory 

 canals conspicuous, parietal foramen large. 

 Teeth conical, of unequal size. Presacral 

 vei"tebrae composed of horseshoe - shaped 

 pleurocentra and hypocentra, the former 

 alone supporting the neural arch. In the 

 caudals the pleurocentra and hypocentra 

 form complete rings, and both elements 

 take part in support of the neural arch, 

 but the haemal arch is borne exclusively by hypocentra. 

 and Illinois. C. heteroclitus, Cope. 



Bijylovertehron, 'Fvitsch (Fig. 198). Imperfectly known. Lower Permian; 

 Bohemia. Brachyops, Owen ; Gondwanosaurus, Lyddeker. Trias (Gondwana 

 Beds) ; East India. 



■ , Bothriceps, Huxley. Skull triangular, with very large parietals, and 

 coarsely sculptured plates. Anterior nares far forwards. Teeth acutely 

 conical, vertically grooved. Trias ; Australia and South Africa. 



Micropholis granulata, Owen sp. Trias ; Table 

 Mountain, South Africa. A, Skull, from above. 

 B, Prom the side 'i/i (after Owen). 



Permian ; Texas 



Sub-Order D. STEREOSPONDYLI. Zittel. 



Vertebrae completely ossified^ slightly amphicoelous, sometimes centrally perforated 

 for passage of the notochord. Basioccipital region ossified ; sensory canals forming a 

 lyra between the orbits and anterior nares. Teeth with complicated infolding of the 

 dentine. 



Family 1. Gastrolepidotidae. Zittel. 



Ventral armour consisting of elongated bony scutes. Badial prolongations of pulp 

 cavity only moderately branched. Carboniferous and Permian. 



