Fossil Reptiles of New- Jersey. 131> 



ynce to the presence of these serratures, although he does not 

 rely upon them alone in establishing his subgeneric division. 

 Sommerring, in his Memoir Ueber die Lacerta gigantea der 

 Vorwelt, describes the edges as sharply toothed.* In the 

 large plate which illustrates the memoir of Sommerring, this 

 serrated appearance is more distinct than in the reduced figures 

 given by Cuvier, but in order to make them evident to the eye> 

 the German Professor has been obliged to represent them mag- 

 nified. Another peculiarity in which the form of the teeth of 

 the Geosaurus, as described by Sommerring and Cuvier, dif- 

 fers slightly from our fossil. A section of the base of the tooth 

 of the Geosaurus shows that the external face is bluntly facetted 

 or divided into three planes — see fig. 5.f The same planesmay 

 be seen in the teeth of the recent Tupinambis. In our speci- 

 men both surfaces are alike divided into four or five small planes 

 — see fig. 4. These differences may serve as one of the specific 

 distinctions, but it is proper to add that Cuvier, in his descrip- 

 tion of the Monheim fossil and with the memoir of Sommer- 

 ring before him, passes over in silence the figure of a section 

 of the base of the tooth as if it was unimportant, or not always 

 a constant character. A comparison of the dimensions of the 

 tooth belonging to the Cabinet of the Lyceum as given above, 

 with those of the Monheim fossil, shows that the former must 

 have been more than twice the size of the latter, and ap- 

 proaching nearer in this particular to the Mosasaurus. 



It will appear, from what has been said, that the tooth now 

 described agrees with those of the Geosaurus in the important 

 particulars of shape, attachment, and manner of dentition. It 



* " Die auswendige Flache der Krone wird von der inwendigen durch 

 cine scharfe schwartze gezahnelte kante abgegranzt." 



f " Die auswendige Flache ist nichl mir weniger convex als die innere 

 Flache, sondern die ueberdies noch der Lange nach stumpfeckig gleich^ 

 sam facetirt." p. 8. 



