SYSTEMATIC REVISION 59 



Genus PANTYLUS Cope. 



Bull. U. S. Geol. Survey of the Terrs., vol. vi, art. ii, 1881, p. 79. 

 Trans. Am. Phil. Soc., vol. xvii, 1892, p. 14. 



Type: A skull. No. 4330 Am. Mus. Nat. Hist. Cope Coll. From Texas. 



Original description: "The superficial ossification is complete, leaving only 

 nostrils, orbits, and parietal fontanelle. Surface sculptured. Mandible with an 

 angular process. Teeth shortly conic, obtuse, and without grooves or inflections, 

 increasing in size toward the anterior part of the jaws. Mandible supporting 

 several rows of teeth which oppose a pavement of obtuse teeth on the palate. These 

 are situated on either the palatine or anterior part of the pterygoid bones. Quad- 

 ratojugal and malar bones well developed. No lyra or mucous grooves." The 

 genus was regarded as Stegocephalian in character, but in the next year was placed 

 among the Reptilia (26). 



In 1892 Cope mentions that Pantylus agrees with Chilonyx in the composition 

 of the cranial root, except that the suspensorium is vertical and not directed forward. 



Revised description: 



1. Skull flat on top with the sides steeply inclined; the posterior surface nearly 



vertical. 



2. Orbits of medium size, near the middle of the skull. 



3. Teeth, blunt, swollen cones. 



4. Maxillary teeth nearly uniform in size except the second or third, which is 



larger. 



5. Teeth in more than one row in lower jaw and probably in the upper also. 



6. Not determinable. 



7. Supraoccipital plate vertical. 



8. Skull with close reticulate sculpture. 



9. 10, II. Not determinable. 



Pantylus cordatus Cope. 



Bull. Geol. and Geog. Survey of the Terrs., vol. vi, art. n, 1881, p. 79. 

 Trans. Am. Phil. Soc, vol. xvii, 1892, p. 25. 



Type: Same as the genus. 



Original description: "The skull of the Pantylus cordatus is about as large as 

 that of the fully grown snapping tortoise, Chelydra serpentina, and has somewhat 

 the same form of outline. The vertex is flat; the postorbital region is swollen, and 

 the muzzle is abruptly acuminate. The orbits are lateral with a slight vertical 

 exposure, and are widely separated. The front is deflected from opposite their 

 posterior margins, and the muzzle protrudes considerably beyond the lower jaw. 

 The premaxillary bones form a triangle whose apex does not appear on the superior 

 surface of the muzzle, and the nares are rather close together, and lateral in their 

 vertical presentation. The upper extremity of the snout is occupied by the large 

 nasal bones, which are followed by the larger frontals. The lachiymal and pre- 

 frontal are both well developed, the latter extending backwards to meet the post- 

 frontal near the superior border of the orbit. The posterior border of the skull 

 is damaged, but enough remains to show that it was concave. The symphysis 

 mandibuli is short. The rami are wide, and are flat below the inferior surface, 

 forming a rounded angle with the interior surface. The angular process is in line 

 with the external border of the ramus. 



"The sculpture of the cranium proper is strong, consisting of pits separated 

 by strong narrow ridges, forming a honeycomb pattern. The fossae are smaller on 

 5 



