EXTINCT BATKACHTA. 369 



MOLGOPHIS BREVICOSTATUS, Cope. 



Represented by portions of the vertebral column of these and perhaps 

 of other individuals obtained by Prof. Newberry during the first season 

 of 1874. One of these includeri nine pairs of ribs, with vertebrae, and 

 another thirteen pairs. The vertebrae are subquadrate in section, and 

 the concavity of the articular faces is not deep. They support strong 

 lateral ridges separated by deep concavities. The heads of the ribs are 

 somewhat contracted, and the shafts present outward a tubercular angle 

 at a distance of one-fourth the length from the head. The remaining 

 part of the shaft is stout, nearly straight, and gradually contracting to 

 an obtuse extremity. They embrace a narrow medullary cavity. In 

 none of the specimens is there any trace of abdominal armature, but 

 abundant remains of the contents of the abdominal cavity, in proper 

 position, are preserved on the blocks. This species is more massive than 

 the M. macrurus, and the ribs are shorter, thicker, and less curved. 



Length of seven vertebrae, .105 m.; length of one centrum, .016; diame- 

 ter of the same vertically, .011; length of a rib on curve, .024; greatest 

 thickness of the same, .0025. 



The specimens exhibit imperfectly preserved neural spines, which ai t. 

 plain, and longer than high. 



MoLQOPHis Wpieatleyi, Cope (species nova). 



Established on a specimen which exhibits about twenty-five vertebrae- 

 with ribs, and the posterior portion of the cranium. No traces of ab- 

 dominal scales or rods, thoracic shields, or limbs are visible. By such 

 negative characters it is referable to the genus Molgophis, although the 

 definition of the latter is as yet incomplete. The present Batrachian 

 may, indeed, be ultimately found to be an Ophiderpeton, to which it also 

 bears resemblance. 



The specimen is that of an animal of very much smaller size than the 

 M. macrurus. The vertebrae are of moderate length, with a low neural 

 spine, and centrum angular at the sides and truncate at the articular 

 extremities when in place. The ribs are rather short, slightly curved, 

 and apparently hollow. Although the vertebral centra are ossified, the 

 elements of the cranium have a larval appearance. These consist of 

 two parallel flat, bony plates, which resemble the frontoparietal bones of 

 a frog; they are slightly separated from each other, but do not inclose a 

 fontanelle. A wedge-shaped bone extends from the outside of the front 

 of each of these, acuminate behind, and widening anteriorly in the 

 position of a postfrontal bone. In front of the posterior border of each. 

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