444 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 52- 



Dimensions of the type-skull of Proinia patagonica 



mm. 



Breadth between the orbits (est.) 292 



Length from posterior margin of the frontal in the median line to anterior 



end of the mesethmoid 121 



Length of the nasal process of the frontal 52 



Breadth of the two nasal processes 86 



Greatest breadth of the orbital process of the frontal 57 



Least breadth between the blowholes 36 



Greatest breadth across zygomatic processes (est.) 350 



Length from surface of occipital condyles to anterior end of basi- 



occipital 91 



Breadth across occipital condyles 112 



Least distance between condyles 9 



Greatest breadth of right condyle 35 



Height of the same 67 



Greatest breadth of basioccipital 159 



Distance from occipital condyle to post-glenoid process of zygomatic 122 



Breadth between exoccipitals (est.) 250 



Length of zygomatic process (apex lacking) 80 



Breadth of glenoid surface ^y 



Breadth of temporal fossa 90 



Length of temporal fossa (est.) 218 



Distance from superior margin of occipital condyles to vertex 140 



Least distance between temporal fossae (est.) 113 



Cervical Vertebra 



This skull is accompanied by a cervical vertebra (fig. jG), col- 

 lected at San Julian by Mr. Hatcher two days before the former. 

 There seems little room for doubt that this vertebra belongs to the 

 same species as the skull. The neural canal has almost the same 

 width as that of the foramen magnum. 



The vertebra resembles the third cervical of Inia in general ap- 

 pearance, but differs from it in size and thickness, and in various 

 details. The centrum is somewhat more than one-half as long as 

 broad ; the neural canal is as broad as the centrum and is about one- 

 half as high as it is broad, while in hiia it is much higher than broad 

 and much less broad than the centrum. The neural spine is some- 

 what broken, but was evidently very small when complete. On ac- 

 count of the length of the centrum and of the top of the neural arch, 

 the anterior and posterior zygapophyses are widely separated, instead 

 of overlapping, as they do in Inia. The zygapophyses themselves 

 are oval, or nearly circular, and quite flat. The anterior pair are 

 directed upward and inward, and the posterior downward and out- 

 ward. The transverse process is very broad, and is pierced by the 



