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University of California Publications. [Geology 



P 3 is badly crushed, but presents no peculiarities as far as 

 can be ascertained. The lower premolar, P 4 , has two well devel- 

 oped posterior cusps behind the protoconid, but does not differ 

 materially from the same tooth in S. neogaeus or S. necator. The 

 superior sectorial presents the least variation from the type of 

 sectorial for the typical Smilodon. It is somewhat smaller than 

 in the South American species, but about the same size as in S. 

 floridanus. The posterior lobe is long and stout, showing' a 

 tendency toward division into two parts. There is a well devel- 

 oped basal tubercle in front of the protostyle. 



The inferior sectorial shows a decided specialization in the 

 development of a distinctly separated basal cusp in front of the 

 paraconid in two specimens (Nos. 10210 and 10258). The proto- 

 conid blade is considerably longer than the paraconid and shows 

 a small heel clearly separated from its posterior border. On 

 plate 13, figure 2, both heel and anterior basal tubercle are 

 shown, though the anterior tubercle has been largely worn away. 

 In the dimensions of M 1 there is some variation. A well worn 

 molar is thicker but shorter than the tooth of a younger indi- 

 vidual. 



Relationships. — The resemblance of this form to Smilodon 

 floridanus is very close. On comparison, the skulls show striking 

 similarities in the general shape and size. Some of the differ- 

 ences are in the fore and aft space of the teeth, and therefore the 

 length of the muzzle, that of the California specimen being some- 

 what shorter. The greatest variation is in the position of the 

 posterior nares, its distance behind the molar series being 23 mm., 

 while in floridanus it is slightly in advance of M 1 . 8. floridanus 

 Leidy is the only skull of a North American saber-tooth cat 

 known to the writer that is in a fair state of preservation, with 

 the exception of the California material. No teeth remain with 

 the Florida specimen, while in 8. calif omicus we have represent- 

 atives of all the teeth. Measurements of the alveoli seem to 

 show that they are about the same size in the two, with those of 

 8. floridanus a trifle longer in anteroposterior diameter. The 

 alveoli of the canines are practically the same size in both speci- 

 mens. While the skulls of the 8. floridanus and 8. calif omicus 



