Permian of New Mexico. 385 



serrated suture. The precise number of teeth I cannot be sure 

 of. On the left side the teeth are hidden by the obliquely 

 compressed mandibles from the outer side ; on the right they 

 are not perfect. Before the parts were cemented together, Mr. 

 Gibb worked out the left maxillary and mandibular teeth from 

 the inner side in large part, and these have been used to com- 

 plete the figures in the drawing. There are at least eighteen in 

 the maxilla, and perhaps more. The anterior ones are longer 

 and stouter, conical like the incisors, and somewhat recurved. 

 Their attachment to the bone is more or less plenrodont. The 

 posterior teeth are shorter, but are also nearly circular at their 

 bases. There is but one row. The nasals are very large bones, 

 occupying nearly the whole of the upper surface of the skull 

 in front of the orbits, and are gently convex or flat. The 

 lachrymals, as in probably all cotylosaurians, are elongate, form- 

 ing the posterior border of the nares and a part of the anterior 

 border of the orbits. As in the Diadectidse, and quite unlike 

 the condition in the Pariotichidae, the small frontals do not 

 take any part in the orbital border, which is formed by the pre- 

 frontals and postf rontals ; as in the Diadecticlse, both these 

 bones are short and broad, extending little beyond the orbit 

 in front or behind. The parietals are short, broad bones form- 

 ing most of the superior surface of the skull back of the orbits ; 

 the parietal foramen is of the usual size, very unlike the enor- 

 mous one of the Diadectidse. The sides of the skull back of 

 the orbit are formed chiefly by the squamosal, very clearly dis- 

 tinct from the small quadratojugal on the lower posterior 

 margin, but not distinguishable at present from the postorbitals 

 and epiotics quite to my satisfaction. Back of the parietals 

 are the narrow transverse dermoccipitals, which seem to be 

 quite distinct from a small bone at the outer angle, which 

 doubtless is the tabulare (epiotic). The structure of the poste- 

 rior part, the occipital region, is somewhat confusing, and I do 

 not feel at all sure of my determinations. The discussion of 

 this region I reserve for a later paper, hoping that additional 

 material may be forthcoming. The structure of the palate, so 

 far as it has been developed in the specimen, is most interest- 

 ing, so closely resembling the " rhynchocephalian" type, that a 

 few years ago, had it been found without other parts of the 

 skull it would have unhesitatingly been located in the " Diap- 

 sida" and " Diaptosauria." The specimen has not yet been 

 thoroughly cleaned in the anterior part, so that I can say noth- 

 ing of the vomers. The palatines and united pterygoids are, 

 as in Labidosaurus and Pariotiehus, separated by a more or 

 less elongated interpterygoidal space. The eminence in the 

 region of the transverse, if the bone be distinct as I think it is, 

 is crowned by a row of five or six teeth, evidently more or 



