ART. 19 A MIOCENE PORPOISE FROM MARYLAND KELLOGG 49 



Measurements of the caudal vertebrae (in millimeters) 



Greatest depth (vertically) 

 of vertebra (tip of neural 

 spine to inferior face of 

 centrum) 



Greatest height of centrum 

 anteriorly 



Breadth of anterior face of 

 centrum 



Greatest height of centrum 

 posteriorly 



Breadth of posterior face 

 of centrum 



Length of centrum 



Distance from base of neu- 

 ral arch (inside margin) 

 to tip of left transverse 

 process 



Maximum width of ex- 

 tremity of left trans- 

 verse process 



Minimum anteroposterior 

 diameter of neurapophy- 

 sis 



Vertical height of neural 

 spine (distance between 

 superior margin of spinal 

 canal and tip of spine)... 



1st 



X 

 X 



27.2 



29. 5 



30. 2 

 39. 5 



55 

 26. 4 

 16.7 



2nd 



X 

 X 



3L 5 



32. 3 



31.5 

 37. 5 



51 



28. 9 



3rd 



X 

 X 



32.7 



X 



31 + 

 7.3 



45 



29. 8 

 16. 9 



X 



6th 



7th 



68.4 

 27 



X 



32.4 



31.2 

 33.8 



40 

 20. 5 



16. 7 



44 



75.3 

 26.8 

 30 



32. 5 



X 



33. 8 



34 

 19.8 

 16. 5 



36 



lOth 



77+ 



X 

 X 



3L S 



33. 5 

 29. 5 



27. 5 



17. 7 



42 + 



11th 



56.6 

 28.3 



X 



32. 8 



27. 5 

 29 



24 



19. 5 



23. 8 



12th 



49. 3 



28.2 



X 



32.7 



26 



28 



21 



21 



16. 5 



13th 



42. 2 

 30. 3 



X 



30. 5 



23. 8 



27.8 



19. 5 



12 



14th 



31 



28 



24. 4 



28.2 



22. 5 

 « 24. 5 



15. 5 



1 Estimated. 



2 Anterior epiphysis missing. 



3 Posterior epiphysis missing. 



CHEVEON BONES 



Four chevron bones are preserved with the skeleton. One of them 

 (pi. 13, fig. 5) belongs with an anterior caudal. It is the largest one 

 of the four and has a wide blade, the anteroposterior diameter at the 

 extremity being equivalent to about two-thirds of the depth of the 

 chevron. Another chevron (pi. 10, fig. 6, and pi. 11, fig. 7) which 

 belongs with some following caudal has a much broader blade, the 

 anteroposterior diameter at the extremity being greater than the 

 depth of the chevron. The inferior margin of the blade of this 

 chevron is curved, while that of the preceding chevron is almost 

 straight. The third chevron (pi. 11, fig. 6) belongs farther back 

 and is smaller, but the anteroposterior diameter of the extremity of 

 the blade is almost equivalent to the depth of the chevron ; the infe- 

 rior free margin of the blade is slightly curved. The smallest (pi. 

 11, fig. 8) of all these chevrons is probably the last in the series and 

 may have belonged with the fourteenth caudal. The blade is very 

 short and the anteroposterior diameter at the extremity is more than 

 twice the depth of the chevron. 



