Cope.] lyb [Dec. 16, 



The typical specimen was found by Wm. Baldwin near the Puerco 

 river, west of the Nacimiento mountain, New Mexico, in the typical 

 locality of the Puerco formation. 



Champsosaurus saponensis, sp. nov. 



Represented in my collection by six cervical and several dorsal vertebrae, 

 one only of the latter with well preserved centrum, parts of ril)s, and 

 various other bones, whose reference is not yet certain. 



The cervical vertebrte include the os dentatum or centrum of the atlas. 

 This shows its streptostylicate character in its distinctness from both the 

 centrum and the free hypapophysis of the axis. Nevertheless it is more 

 Crocodilian than Lacertilian in form. Its anterior face is transverse, with 

 a little lip carrying forwards the floor of the neural canal, below which the 

 face is leveled posteriorly. The inferior surface is narrow and .transverse, 

 as though adapted for the anterior part of the hypapophysis of the axis. 

 At each side it terminates in a prominent tuberosity, as though for the 

 attachment of a cervical lib as in theCrocodilia. The anterior face is 

 bounded posteriorly by a transverse groove which terminates in a fossa 

 on each side. The posterior articular face of the os dentatum is wider 

 than deep. The lateral angles of the superior face are rounded, and its 

 median portion is concave. 



The axis displays a large facet for the hypapophysis. Behind it the 

 inferior middle line is not keeled, but is coarsely wrinkled longitudinally. 

 The posterior edge of the hypapophysial facet is the most prominent part 

 of the inferior surface. The posterior articular face is deeper than wide. 

 This is true of the faces of all the cervical vertebrae. The latter gradually 

 increase in size posteriorly, and the dorsals become larger. The articular 

 faces of all the centra are regularly rounded and not contracted below. 

 The five cervicals are strongly keeled below ; the keel of the third centrum 

 being split up anteriorly into narrow ridges. On the sixth the keel is 

 more prominent and acute. The dorsal is not keeled. A trace of the 

 parapophysis appears low down on the fourth cervical ; it rises and 

 becomes prominent as a round tuberosity on the fifth and sixth. It ap- 

 pears on the superior edge of the centrum of the dorsal vertebra, where 

 it is connected with the diapophysis. It is near the middle of the length 

 of the centrum, and not near the anterior border as in G. australis. 



The surfaces of the vertebriE are very smooth excepting where tlirown 

 into coarse wrinkles near the borders of the articular faces and near the 

 hypapophysis. The edges of the articular fixces are somewhat revolute 

 on the sides in the cervicals, but not on the dorsal. They are impressed 

 in the centre to a point, most strongly so as we pass forwards in the 

 series. There is a fossa below the space anterior to the parapophysis of 

 the dorsal vertebra, which is abruptly bounded below by a horizontal 

 angle. A separate neural spine perhaps of a cervical vertebra, has the 

 following form. It is stout, and is contracted rather abruptly at the apex 

 from behind forwards. The section is broadly lenticular, angulate in 



