312 University Geological Survey of Kansas. 



ground, and finally concluded, as Doctor Leidy had already 

 done, that the name Saurodon should be no longer used. 



It has since been shown that there are two distinct genera, 

 the differences being found mainly in the more slender mandi- 

 ble and the occurrence of deep notches instead of foramina at 

 the bases of the crowns of the teeth in Saurodon. There is also 

 some difference in the shape of the teeth in the two forms. 



Below is given a list of the known American species : 



Saurodon leanus Hays, Marl, New Jersey. 



Saurodon phlebotomus Cope, Niobrara Cretaceous, western Kansas. 

 Saurodon broadheadi Stewart, Niobrara Cretaceous, western Kansas. 

 Saurodon xiphirostris Stewart, Niobrara Cretaceous, western Kansas. 

 Saurodon ferox Stewart, Niobrara Cretaceous, western Kansas. 



Saurodon phlebotomus. Plate LVII, figs. 4 and 5. 



Daptlnus phlebotomus Cope, Cret. Vert. West, p. 213. 

 Savrocephalus phlebotomus Cope, Proc. Am. Phil. Soc. 1870, p. 530: 

 Hayden's Ann. Rep. U. S. Ceol. Surv. 1871, p. 416. 



There are remains of several specimens of this species, in- 

 cluding the jaws, vertebrae, and portion of one skull, in the mu- 

 seum. 



The maxilla is more slender than in S. broadheadi, and the 

 surface for the premaxilla is bent inward very strongly, al- 

 though this may be due to distortion. The alveolar border is 

 nearly straight, and has alveoli for twenty-nine subcylindric 

 teeth, which have the characteristic notches for nutrient ves- 

 sels at the base of each. The posterior extremity of the border 

 is edentulous, curved slightly upward. The condyle for the 

 palatine is not elevated as in Xiphactinus, and is flatter than in 

 Saurocephalus. The internal side of this condyle is invaded by 

 a slight notch, which is absent in 8. broadheadi and S. ferox. 

 The anterior condyle is broken away, but it seems to have been 

 elevated upon a slight pedestal, and was probably very small. 

 The upper portion of the bone is striated ; the lower portion, just 

 above the alveolar border, is covered with numerous punctations. 



The dentary is slender, and the symphysis is not so straight 

 as in Saurocephalus dentatus, but is slightly convex in front, with- 

 out* the prominent bony tubercles which are so pronounced on 



