128 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



from outer to inner margins. The postzygapophysial facets are much 

 smaller and less sharply outlined than those of the eighth dorsal. A 

 slight increase in the length of the centrum also distinguishes this 

 vertebra from that of the eighth dorsal; the transverse width of 

 the posterior surface (40.5 mm.) of the centrum is only slightly 

 greater than the corresponding measurement of the anterior surface 

 (39.5 mm.) 



Measukements of dorsal vertebrae (in millimeters) 



D.4 D.6 D.8 D.IO 



Greatest vertical height of vertebra, 

 ventral face of centrum to tip of 

 neural spine 78.+ 80.+ 102.5 119. + 



Vertical height of neural spine, dorsal 

 surface of neural canal to tip of neu- 

 ral spine 



Greatest anteroposterior diameter of 

 centrum 



Greatest transverse diameter of an- 

 terior face of centrum 



Greatest vertical diameter of anterior 

 face of centrum 



Greatest vertical diameter of neural 

 (spinal) canal anteriorly 



Greatest transverse diameter of neural 

 (spinal) canal anteriorly 



Least anteroposterior diameter of pedi- 

 cle of neural arch 



Distance across vertebra between outer 

 ends of diapophyses 



Greatest distance between outer mar- 

 gins of prezygapophysial facets 



Greatest distance between outer mar- 

 gins of postzygapophysial facets 



Distance between tip of metapophysis 

 and posteroventral angle of neural 

 spine 63.5 67.0 69.5 67.+ 



CAUDAL VERTEBRAE 



The terminal caudal (USNM 20659), probably the third or fourth 

 (pi. 11, fig. 2) from the distal end of the vertebral series, resembles 

 the corresponding vertebra of Inia geqffrensis. The dimensions in 

 millimeters are as follows: Greatest width, 34; vertical diameter of 

 anterior surface, 18; and anteroposterior diameter, 15. Short, blunt 

 upper and lower processes are formed on each side by the medial side 

 to side constriction of the centrum. The anterior surface of the 



