1877.J iod [Cope. 



as the latter. The angle separating them is not continued on the apical 

 third of the crown. The section of the antero-external face is nearly plane. 

 The division of the interior or flatter face is similar, but the angle is less 

 pronounced. The anterior and narrower face is slightly concave. In this 

 crown, as in the first described, there are weak transverse undulations 

 near the basal third. 



Measurements. M. 



Length of anterior tooth preserved 080 



Length of crown of same 055 



antero-posterior 022 



f an 

 jtra 

 antero-posterior 010 



Diameter of base of crown , 



ransverse 016 



Diameter near apex of same . 



( transverse 008 



Length of posterior tooth preserved 040 



Length of crown of second tooth 029 



Antero-posterior diameter at base of crown .025 



" " at middle of crown 019 



Transverse diameter " " " 010 



These dimensions indicate an animal of the general proportions of the 

 gigantic carnivorous Dlnosauria of the genera Lcelaps, Megalosaurus and 

 Teratosaurus. They exceed those of the Bathygnathus borealis and the 

 only known species of G ladiodon, G. lloydii. 



The characters which demonstrate that this Saurian belongs to a genus 

 distinct from any of the above are, Firstly, the presence of the external and 

 internal longitudinal ridges which divide the crown of the posterior tooth 

 into four facets. Second, the shortness of the crown as compared with 

 its width, a point in which it approaches Palceosaurus. Thirdly, the 

 semicircular section of the anterior tooth, a form not found in either Ba- 

 thygnathus or Teratosaurus, where almost the entire series is known . It 

 is only approximated in some of the Western species referred to Lcelaps, 

 but is not inconsistent with the characters of that genus as represented by 

 them. 



To the genus thus characterized, the name Palceoetonus is given, and 

 to the species, the name Palceoetonus appalachianus. 



Associated with the teeth of this species, were found several leaves 

 resembling those of Pterophyllum; and stems of Galamites occur in the 

 same locality. 



Additional specimens received from Mr. Wheatley include anterior, in- 

 termediate and posterior teeth of a larger animal than the one above 

 described, and intermediate and posterior teeth of a much smaller indi- 

 vidual of probably the same species. 



The large half-conical tooth of the large individual, presents a slight 

 groove-like constriction at the basal portion of the posterior cutting edge. 

 Length of crown above base .060 ; width at base .025. "Width of posterior 

 tooth at base .030. The form of the intermediate tooth is between those 

 of the others. Its external face is very convex and is not faceted. The 



