ART. 10 



A MIOCENE PORPOISE FEOM MARYLAND KELLOGG 



41 



seventh dorsal, and the same holds true for the neural arches. The 

 anterior margin of the neural spine is more strongly curved than the 

 posterior margin. 



Ninth dorsal. — This dorsal (pi. 9, fig. 2) is characterized by a short 

 transverse process (parapophysis) with a wide facet on the extremity 

 for a single-headed rib. The centrum is elongated and constricted 

 from side to side mesially. The anterior epiphysis is loose and pro- 

 jects laterally beyond it on the left side. The metapophyses are 

 large and project obliquely upward. 



Tenth dorsal. — The centrum (pi. 9, fig. 3) is longer than broad and 

 the neural arch is slightly wider than on the ninth vertebra. There 

 is a large facet for a single-headed rib on the extremity of the long 

 parapophysis which projects laterally from middle of the centrum. 

 There are some points about the restored right parapophysis which 

 are incorrect. The parapophysis on the left side is complete and the 

 description is based upon this process. The neural spines of the 

 ninth and tenth dorsals are similar in shape and proportions. The 

 metapophyses are large and the postzygapophyses are very much 

 reduced in size. The posterior epiphysis is missing, but the anterior 

 epiphysis is attached to the centrum. 



Measurements of the dorsal vertebrae (in millimeters) 



• One epiphysis missing. > Both epiphyses missing. ' Estimated, right parapophysis destroyed. 



