64 



cave, and at each end of the lower side there is an obtuse hypapophysial 

 tuberosity. The sides of the centra of both vertebrae are concave. The 

 neural canals are relatively small, and the neurapophyses co-ossified. A third 

 vertebra, without arches, is similar in specific gravity, though without the 

 white surface-layer of the others. It is appropriate in size and form to this 

 species, and is peculiar in its flat form, resembling the anterior dorsals of Ha- 

 drosaurus. In this respect, it is related to the shorter vertebra of the two 

 above described as the latter is to the longer. The surface of the posterior 

 articular face is damaged. It was not concave, and is now slightly convex. 

 The anterior is preserved, and is concave. 



POLYONAX MORTUARIUS, Cope. 



The articular faces are deeper than wide in the vertebrae ; the sides are 

 smooth ; the lower face is narrowed and probably keeled. 



Measurements. 



M. 

 Anterior dorsal : 



Length of the centrum 0. 048 



Elevation to tbo neural canal 0. 094 



Width 0.094 



Median dorsal: 



Length of the centrum 0. OW 



Elevation to the neural canal 0. 117 



Width 0.083 



Posterior dorsal : 



Length of the centrum 0. 092 



Elevation 0.101 



Width 0.083 



Diameter of the neural canal 0. 010 



The measurement of the neural canal is made near the base of the neura- 

 pophyses, and is probably a little affected by pressure. 



The limb-bones embrace portions of tibia, fibula, and some others not 

 yet determined. The portion of tibia is from the base of the cncmial crest, 

 so that one extremity is trilobate, the other transverse-oval. The former 

 outline indicates two posterior tuberosities. The bone is solid, and the 

 superficial layer for '6 mm or less, is so dense and glistening as to resemble 

 cement um. Portions referred to fibulae have a subcrescentic section, with 

 narrowed width in one direction. Two fragments of shafts of long bones I 

 cannot determine, but they may belong to the pelvis. They belong to opposite . 

 sides; each is oval in section, and the diameter regularly contracts to one 

 end. One side is slightly convex in both directions ; the other is less con- 



