305 



denticles are absent. Most of the teeth appear slightly water-worn, but the 

 best of them exhibit no trace of the lateral denticles. These specimens were 

 obtained by Mr. Gabb from the Cretaceous green sand of Mullica Hill, Glou- 

 cester County, New Jersey. 



Fig. 50 represents a tooth which lies partially imbedded in a fragment of 

 gray sandstone, obtained by Professor Hayden from the Cretaceous deposit, 

 indicated by him as No. 2, near the mouth of Vermilion River, Kansas. In 

 the attempt to dislodge the tooth from its matrix the ends of the root were 

 broken off, but it is otherwise complete. It also appears not to have pos- 

 sessed lateral denticles, but-otherwise is like the teeth of L. elegans. 



Roemer describes and figures a tooth, (Kreidebildungen v. Texas, page 29, 

 Plate I, Fig. 7,) under the name of L. Texana, from the Cretaceous forma- 

 tion of Texas. The figure represents what appears to be a perfect tooth 

 without lateral denticles, and otherwise resembles those of L. elegans. 



Dr. B. F. Shumard also submitted to my inspection several teeth from the 

 Cretaceous formation of Texas resembling those of L. elegans, but in these 

 the root was broken off, excepting on one side of one specimen, and in this 

 no lateral denticle existed. 



Notwithstanding all that has been stated above, I must add that I have 

 noticed among collections of teeth of L. elegans from Tertiary formations 

 specimens in which the lateral denticles were feebly developed, and others in 

 which they were entirely absent. In some of the latter, traces of their acci- 

 dental detachment were perceptible, but in others I could see none. 



It would appear, however, from the facts thus given, that during the Cre- 

 taceous period there existed two species of sharks in which the teeth resem- 

 bled those of L. cuspidata and L. elegans of the Tertiary period, except that 

 the teeth possessed no lateral denticles. The two Cretaceous sharks were 

 probably the ancestors from which the species just named were evolved. 



OTODUS. 



Otodus divaricatus. 



Among a small collection of fossils submitted to me for examination by Dr. 

 William Spillman, of Columbus, Mississippi, there is a specimen of a shark- 

 tooth of rather peculiar character, which is represented in Figs. 26 to 28, of 

 Plate XVIII. The specimen is labeled " lime formation," Texas, and notli- 

 39 g 



