14 A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



3. The third, fourth, and fifth ribs expanded into broad triangular plates. 



The sixth, seventh, and eighth overlain by slender plates. 



4. Transverse processes of the vertebrae extending beyond the zygapophyses. 



There seems to be no valid reason for retaining the genus Empedias. As 

 explained in the description of the family, the genera were separated largely on the 

 character of canine teeth. More than once Cope altered his definition of the genus 

 as his opinion of the value of the presence or absence of the supposed canines and 

 of the more or less molariform character of the cheek teeth varied. The condition 

 of the specimens does not permit a successful effort to separate them into two groups 

 according to Cope's description and so the genus Empedias is dropped. 



Diadectes sideropelicus Cope 



Proc. Am. Phil. Soc, vol. xvn, 1878, p. 505. 

 Proc. Am. Phil. Soc, vol. xxxv, 1896, p. 133. 



Type: The same as that of the genus. 



Original description: "The lateral tuberosity of the teeth already described is 

 on the most elevated, hence opposite, borders of the crowns in the two jaws. It 

 differs in its degree of prominence in different teeth, but is subject to attrition in one 

 of the jaws at least. The form of the principal worn surface is an elongate oval. 

 The investing layer of the crown is perfectly smooth, excepting between the lesser 

 and the greater cusps, where the obtuse edge is slightly longitudinally grooved. The 

 surface of the jaws is not sculptured. 



" Measurements. 



M 



"Greatest elevation of a tooth (No. I ) . . 0.0 11 



Diameters of crown: 



Transverse 006 



Anteroposterior 012 



Four teeth occupy 042 



Four alveoli of (specimen) No. 2 occupy 024 



"The jaws are as large as those of a medium sized alligator." 



In 1896 Cope showed that the specimen No. 2 was a distinct species (see D. 

 biculminatus) and redefined D. sideropelicus: 



"This species is represented by a left maxillary bone which contains three 

 molar teeth in place and spaces for five or six others. A simple tooth at its anterior 

 part is larger than is usual in the species of this family. I have accordingly defined 

 the genus Diadectes as characterized by the presence of a canine tooth. It is, 

 however, not possible to determine whether the other simple teeth may not have 

 been of equal proportions, as they are represented by the alveoli in the specimen. I 

 therefore define the genus by the molar characters, which are distinct. In this re- 

 spect the species D. latibuccatus and D. phaseolinus agree with it. In the last named 

 the heel of the molars is larger than in the two others, approaching remotely the 

 genus Empedias. The D. latibuccatus differs from the D. sideropelicus in the smaller 

 number of the molar teeth, and more numerous caniniform teeth." 



Revised description: The type specimen is a fragment of the left side of the 

 lower jaw instead of a portion of the maxillary, as described by Cope. The whole 

 specimen is in a wretched state of preservation and there are three imperfect teeth. 

 The crowns of all are so worn that it is impossible to distinguish them from other 

 species of the genus. The species is indeterminate. 



