'25 



terior dorsals of the Radrosaurus. lu 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 MOETUARIUS, Cope. 



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

 are smooth ; the lower faces narrowed and probably keeled. 



Measurements. 



M. 



Anterior dorsal, length of centrum 048 



Anterior elevation to neural caual " 094 



Anterior width 094 



Median dorsal, length of centrum 057 



Median elevation to neural canal 117 



Median width 083 



Posterior dorsal, length of centrum 092 



Posterior dorsal, elevation .104 



Posterior dorsal, width .083 



Posterior dorsal, diameter of neural canal 015 



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

 aeurapophyses, 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 cnemial 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 three, MM. or less, is so dense and glistening as to 

 resemble cementum. Portions referred to fibulae have a subcrescentic 

 section, with narrowed width in one direction. Two fragments of shafts 

 of long bones I canuot determine either as belonging to the limbs or 

 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 convex transversely, and gently con- 

 vex longitudinally. A peculiarity consists of a central cavity present 

 in both at the fractured large end, which is bordered by a layer of dense 

 bone like the outside. 



Measurements. 



Transverse diameter of tibia fragment below cnemial crest 125 



Anteroposterior diameter of tibia fragment at base of crest 095 



Width of fragment of fibula 073 



Thickness of do 035 



Length of fragment of unknown bone 145 



Proximal diameter of unknown bone 088 



Distal do. 065 



The above measurements indicate a much larger animal than the 

 Cionodon arctatus, and one not very different in size from the Laelapg 

 aquilunguis. 



