MIOCENE PORPOISES — KELLOGG 113 



' . Greatest breadth of braincase across 



parietals 134. 



Distance from apex of supraoccipital to 

 upper margin of foramen magnum 



Height of foramen magnum 



Width of foramen magnum 

 r Greatest distance between outside margins 

 of occipital condyles 



Greatest height of right condyle 



Greatest breadth of right condyle 



Right upper jaw, 27 alveolae in an inter- 

 val of 



Left upper jaw, 25 alveolae in an interval of 

 ( Left maxillary, 1st to 9th alveola (count- 

 ing forward) 93. 86. 5 



Right maxillary, 1st to 15th alveola (count- 

 ing forward) 161. 



Left maxillarj', 14th to 23d alveola (count- 

 ing forward) 162. 



Left maxillary, anteroposterior diameter of 



23d alveola 14. 



Distance between inner margins of alveolae 



of hindmost teeth in opposite maxillaries 96. 5 80. 



Distance between inner margin of 15th 

 alveola in right maxillary and 14th 

 alveola in left maxillary (counting for- 

 ward) 31. 



Distance from right antorbital notch to 

 posterior margin of hindmost alveola in 

 right maxillary 50. 5 



The outer surface of the premaxillary is convex and the maxillary 

 increases in depth anteroposteriorly as on the skull. The relations 

 of the bones comprising the ventral surface of this rostral fragment 

 correspond rather closely with those noted on the skull. 



MANDIBLES 



The mandibles (pi. 4) of this fossU porpoise exhibit many of the 

 characteristic inid features, including the fu-mly ankylosed symphysis. 

 They differ from those of Inia geqffrensis by having a relatively 

 shorter symphysis, a more gradual slope from the vertex of the 

 coronoid process to the hindmost alveola, and more than twice the 

 number of teeth situated behind the level of the hinder end of the 

 symphysis. 



On these fossil mandibles the symphysis is equivalent to 33 percent 

 of the length of the left ramus in contrast to 57 percent for Inia. The 

 symphyseal portion of the mandibles as well as the interval between 

 the tooth rows are relatively wider than in Inia, and the anterior 



