50 A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



Family SEYMOURIDAE Williston. 

 Jnl. Geol., vol. XJX, 1911, p. 237; Science, vol. xxxiii, 1911, p. 851. 



1. Skull size of LabtJosaurus. A large epiotic notch, quadrate exposed but 



without posterior hook. Surface of skull rugose. 



2. Median incisors not enlarged. Cheek teeth simple cones, none enlarged. 



3. Teeth in a single row ( ?). 



4. An intertemporale present. 



The skull of Conodedes is in a very poor state of preservation and is largely 

 restored in plaster. The general form of the skull is amphibian and the otic region 

 is excavated to show the quadrate. The notch which reveals the quadrate is 

 elongate and the anterior end is continued downward and inward as a deep pit or 

 notch. There is a single row of bluntly conical teeth in both jaws; the broken 

 bases do not show any radial arrangement of the dentine. The palatines and the 

 pterygoids are broad plates, the latter bones nearly meeting in the median line. 

 Both palatines and pterygoids are devoid of teeth. 



The nature of this animal is very uncertain, but it certainly is very different 

 from the Diadectosauria. It might be considered as an amphibian, were it not for 

 the condition of the pterygoids. The nearest form to Conodectes is Seymouria Broili, 

 and I propose to unite them in the (zmily Seymourida to replace the family Otocalida 

 eliminated by the removal of Otoccelus to the Amphibia.* 



Genus SEYMOURIA Broili. (Plate 13.) 



Seymouria baylorensis Broili. 



Paleontographica., Bd. Li, 1894, p. 82. 

 Anat. Anzeig., Bd. xxv, 1904, p. 37. 



Type: Two incomplete skuUs in which the anterior end of the snout is wanting. 

 One has the pectoral girdle and a few vertebrae. Nos. 17 and 18, xv, 1901, Mus. 

 Alte Akademie, Munich. From West Coffee Creek, Willbarger County, Texas. 



Original description: "Contour of the skull triangular. Auditory notches 

 present. Upper surface nearly flat, but the sides and the occipital region steeply 

 inclined. Orbits lateral, large and circular, more in the posterior than in the ante- 

 rior half of the skull. Parietal foramen present. Surface with a rough radiating 

 sculpture which sometimes ceases at the border of a bone and sometimes passes 

 over to the next one. The supraoccipital and tabulare form a small crescentic 

 plate, which is sharply set off from the upper portion of the skull and is inclined 

 steeply to the rear. The parietal is large and broad. The nares are only partly 

 preserved. Orbital ring formed by the postorbital, prefrontal, postfrontal, lachry- 

 mal, and jugal. Auditory notch formed by the tabulare, squamosal, prosquamosal, 

 and quadratojugal. An intertemporal bone present. The maxillary begins directly 

 under the eye, and the largest tooth (so far as the imperfect dentition shows), is 

 rather far forward. The basioccipital is but little exposed and carries a well-formed, 

 slightly concave occipital condyle. The basisphenoid is flat on the median line 

 and the sides are elevated into keel-like processes. Parasphenoid rostrum present. 

 The pterygoids do not meet in the median line posteriorly, but come together at the 

 anterior portion. The external process of the pterygoid, which borders on the 

 palatal vacuity, does not show the strong swelling that appears in Captorhinus 



* The name Seymouridae was published bj Wfllitton, after thii irtide wa> in proof, ai be wai unaware that I had uaed 

 k in the manutcript. — E. C. C. 



