ART. 26 EEMAINS OF FOSSIL PORPOISES KELX.OGG 



Measurements of caudal vertebrae {in ^nillimeters) 



Measurements 



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



inferior face of centrum) _ 



Greatest deptli of neural canal anteriorly 



Greatest breadth of neural canal posteriorly 



Height of anterior face of centrum 



Breadth of anterior face of centrum... 



Height of posterior face of centrum 



Breadth of posterior face of centrum 



Length of centrum. 



Distance across vertebra between tips of the parapophyses 



Distance across vertebra between tips of the prezygapophyses.. 



Minimum length of neurapophysis 



Anteroposterior length of neural spine in a horizontal line im- 

 mediately above the zygapophyses 



Vertical height of neural spine (distance between superior 



margin of neural canal and tip of spine) 



Maximum thickness of posterior epiphysis 



Fifth 



142 

 28 

 8.5 

 60.5 

 67.7 

 66 

 67 

 87.5 



53 

 9.3 



Eighth 



93 



8.7 

 61.7 

 64.7 

 64 

 58.6 

 86.5 

 92.2 

 38.2 

 46 



Tenth 



82 



8 



7.2 

 63 



61.5 

 65 

 52.6 



30.5 

 51 



Four- 

 teenth 



54.6 



61.2 



53 



47 



44.3 



61.6 



31 



Eigh- 

 teenth 



30 



29 

 35.7 



Epiphysis missing. 



All the ribs found with this specimen are imperfect. The proxi- 

 mal portions of 10 ribs are sufficiently well preserved to permit ac- 

 curate description. The extremities only of two other ribs were 

 found. This fossil porpoise probably possessed 11 pairs of ribs of 

 which the first pair are the shortest. When these ribs are arranged 

 in w^hat appears to be their normal position, the external curvature 

 of the anterior ribs is seen to be less pronounced than that for those 

 near the posterior end of the series. 



The neck of the first rib (pi. 14, fig. 1) is flattened, relatively deep, 

 and bears a short quadrangular-shaped capitulum at the extremity. 

 The tuberculum is subovoidal, concave, with a noticeable mesial 

 depression. The shaft is also flattened. 



Only the neck of the second rib (pi. 14, fig. 2) was found and it is 

 also deep and rather short, but the capitulum is larger and more 

 ovoidal than that of the first rib. The tuberculum is also ovoidal, 

 but is not so noticeably depressed mesially. There is a concavity 

 on the posterior face of the neck. 



The neck of the third rib (pi. 14, fig. 3) is narrower than that of 

 the second, with an evident constriction. The capitulum is trape- 

 zoidal in outline. The tuberculum is elongate, nearly subtriangular 

 in outline, and somewhat depressed mesially. Between the tubercu- 

 lum and the angle the external face of this rib is flattened, with a 

 flaring posterior margin. 



In depth the neck of the fourth rib (pi. 14, fig. 4) is about equal 

 to the breadth. The increase in length of the neck corresponds to 

 the change in relative position of the facets on the corresponding 

 vertebrae for the capitulum and tuberculum. These facets are 

 roughly triangular in outline. The external face of this rib is flat- 

 ened with projecting anterior and posterior margins. This flattened 



