VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 241 



From the most perfect specimens I derive the following characters : — The 

 superior incisors are peculiar in having well-marked cingular tubercles at the base 

 internally. In I. 1 and 2 there are two such tubercles which are separated by a 

 notch" of the base of the crown ; in I. 1 they are subequal, while in I. 2 the external 

 is larger. In I. 3 the internal has disappeared and the external is at the external 

 base of the crown. The principal cusp of I. 1 and 2 are compressed so as to be 

 transverse in section ; while in I. 3 the section is nearly round. The size increases 

 rapidly from I. 1 to I. 3, and I. 2 is in all other respects intermediate between I. 1 

 and I. 3. 



The superior canine has a long and rather slender crown which projects well 

 below the flange of the lower jaw when the mouth is closed. It is strongly com- 

 pressed throughout, and one side of the crown is little more convex than the other. 

 The curvature is moderate, and the width of the crown is not greater below than at 

 the alveolar margin. The edge is smooth and sharp and free from denticles. In 

 the absence of denticles it resembles the canine of the species of Smilodon when 

 known, and differs from those of most of the species of Machcerodus, but not 

 from all. 



The molar dentition is pin. \ m. \. The third superior premolar is small and 

 one-rooted. The crown is oblique to the root, is without cusp, and is elongate oval 

 in horizontal section. The second premolar is of moderate dimensions and the roots 

 are well separated. The crown is compressed, and has besides the median cusp a 

 median posterior cutting lobe, an anterior basal lobe which reclines posteriorly on 

 the main cusp, and a vertical heel-lobe. The pm. 1 or superior sectorial is very 

 large. In this specimen all of the crown anterior to the metaconid or blade is worn 

 away, so that I refer to the description of specimen No. 2 for its characters. 



The inferior incisors increase rapidly in size from the first to the third, and the 

 canine follows immediately with an increase of dimensions in the same ratio. I. 1 

 is quite small ; I. 1 and 2 have a basal tubercle at the external side of the crown, 

 and the principal cusps are conic and slightly incurved. The crown of the canine 

 is similar except that it lacks the basal lobe. The second premolar is one-rooted 

 and has a low crown, Avhich consists of a principal cusp and a low-conic heel. It is 

 separated from the first premolar by a space equal to its long diameter. The first 

 premolar is rather large and is more compressed throughout than the corresponding- 

 tooth in the large species of Uncia. Its principal cusp is directed more obliquely 

 posteriorly than in Uncia. There is a well-developed and sharp-edged, but rather 

 low posterior lobe, and a cingular heel-lobe. The anterior basal lobe is small 

 and is posterior to the basal border of the crown. The inferior sectorial has the 

 posterior cutting edge (protoconid) considerably longer than the anterior (paraconid), 

 although its root is much more slender than that supporting the latter. The 

 external base is quite convex outward. 



The flange of the mandible projects moderately below the mandibular border, 

 and is regularly convex in outline. The symphyseal region is concave anteriorly. 



31 JOUEN. A. N. S. PHILA., VOL. XL 



