28 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63. 



On the dorsal surface of the upper transverse process and adjacent 

 to the large canal is a depressed area. A small circular foramen 

 connects this area with the vertebrarterial canal, and may represent 

 the foramen for the exit of the spinal nerve. The lower transverse 

 process is rounded and attenuated. 



The posterior articular facets (pi. 12, fig. 3) for the axis are 

 elongate with nearly straight vertical external margins and are in- 

 distinctly set off from the posterior face of the centrum. The 

 hyapophysial process is short, thick, and irregularly pitted or 

 roughened. 



Measurements of cervical vertebra (in millimeters). 



Greatest depth (vertically) of vertebra (tip of neural spine to inferior 



face of centrum) 89.5 



Anterior breadth of spinal canal 53.5 



Median depth of spinal canal (anteriorly) 47.0 



Distance between tip of one lower transverse process (parapophysis) 



and tip of opposite one 121.0 



Greatest distance across vertebrae between outside margins of anterior 



articular facets 113. 5 



Greatest height of articular surface for condyle 53.2 



Greatest breadth of articular surface for condyle 30.0 



Distance across vertebra between tips of upper transverse processes 



(diapophyses). (Outside measurement) 131.0 



Greatest length of superior face (neurapophysis) of vertebra 37.5 



Greatest diameter of vertebrarterial canal 14.2 



Distance from anterior face (inferiorly) to tip of spinous process 



(posteriorly) 39. 



Greatest length of lateral face of vertebra 67. 5 



Distance from tip of upper transverse process (diapophysis) to tip of 



lower transverse process (parapophysis). (Outside measurement)— 64.0 



DORSAL VERTEBRAE. ^ 



Comparisons have been made between this vertebral column (pi. 

 10) and those of Inia (jeoffrensis (Cat. No. 49,582, U.S.N.M.) and 

 Platanista gangetica (Cat. No. 172,409, U.S.N.M.) Ten dorsal 

 vertebrae are preserved and represent a continuous series. With the 

 exception of the fourth dorsal (pi. 13, fig. 2) which lacks the an- 

 terior epiphysis, all of them are practically complete. The dorsals 

 differ noticeably from those of Inia and to a less extent from those 

 of Platanista. Unfortunately the only skeleton of Platanista avail- 

 able for comparison belongs to a young individual. The vertebral 

 column of Inia includes thirteen dorsals and three lumbars while 

 that of Platanista includes ten dorsals and eight lumbars. As re- 

 marked above ten dorsals are known for this fossil porpoise and in 

 addition it possessed at least four lumbars. 



