ART. 27 A FOSSIL PHYSETEROID CETACEAN KELLOGG 7 



part to differences in the direction of the teeth in the alveoli, the 

 former being implanted more obliquely than the latter. Thin ridges 

 which encircle the dentinal axis and which have been referred to as 

 annular lines of growth are present. Longitudinal grooves or fluting, 

 varying in number and in depth among the several teeth at hand, 

 further characterize the external surface of the dentinal axis. The 

 teeth of Scaldicetus caretti^ a physeteroid whale from the Anversian 

 of Belgium, agree with those of this Californian species in size. 



All of the teeth are imperfectly fossilized and the dentine especi- 

 ally is rather soft and pithy. In their present state, difficulties which 

 are familiar to anyone who has attempted to preserve tusks of 

 mastodons, are encountered when the teeth are freed from the matrix. 

 The teeth fracture and crumble even when every precaution is taken 

 for their preservation. 



Measurements of the rostrum and mandibles 



mm. 



Total length of rostral fragment along the median line 845 



AVidth of right premaxilla at proximal end of rostral fragment 97 



Width of right premaxilla at level of second alveolus 91 



Depth of right premaxilla at proximal end of rostral fragment 190 



Depth of right premaxilla above maxillary suture at level of fifth 



alveolus 69 



Breadth of rostral fragment at proximal end (left maxillary surface 



worn off) 405 



Breadth of rostral fragment at point 100 mm. posterior to distal end 170 



Breadth across combined premaxillae at proximal end of rostral frag- 

 ment 213 



Breadth across combined premaxillae at level of fifth alveolus 211 



Total length of fragment of right mandible 965 



Depth of right mandible at proximal end 192 



Depth of right mandible at extremity 117 



Breadth of right mandible at proximal end 175 



Breadth of right mandible at extremity 123 



Total length of fragment of left mandible 920 



Depth of left mandible at proximal end 196 



Depth of left mandible at extremity 115 



Breadth of left mandible at proximal end 180 



Breadth of left mandible at extremity 117 



Greatest transverse diameter of root of first tooth, left mandible 54 



Greatest transverse diameter of root of second tooth, left mandible 74 



Greatest transverse diameter of root of third tooth, left mandible 70 



Greatest transverse diameter of root of fourth tooth, left mandible 66. 5 



Greatest transverse diameter of root of fifth tooth, left mandible 67. 5 



Greatest transverse diameter of root of sixth tooth, left mandible 70 



Greatest transverse diameter of root of seventh tooth, left mandible 78. 5 



Greatest transverse diameter of root of eighth tooth, left mandible 89 



Greatest transverse diameter of root of ninth tooth, left mandible r»0. 5 



Greatest transverse diameter of root of tenth tooth, left mandible 71 



Length of enamel crown of third tooth, right mandible (apex missing 

 or worn off) 30+ 



