LEIDY'S DESCRIPTION OF A NEW SPECIES OF CROCODILE 137 



a circumstance, however, which is the ordinary one in the living species of 

 Crocodile. 



The second specimen of the teeth, represented in figure 3, consists of a crown only, 

 which is as long as that of the former tooth, but slightly more slender, and the enamel 

 is a little smoother, and its ridges, though not so elevated, are longer. 



The color of the dentinal substance and osteo-dentine of the teeth is umbreous 



brown or chocolate ; the enamel is lighter colored, glistening, and delicately 



undulating and interruptedly striate. 



Measurements. 

 First specimen : 



Thickness of the broken edge of the pulp cavity, three inches below the summit of the crown, 1 1 lines. 



Probable length of the tooth in its perfect condition, if the parietes of the pulp cavity decreased 



in thickness at the same rate as a corresponding tooth of Crocodilus biporcatus, - 5 inches. 



Length of crown laterally, -.--..... If inches. 



Lateral diameter of base of crown, - - . - - - - -10 lines. 



Transverse « " « ...-:... 9| lines. 



Lateral diameter of fang, - - - - - - - -12 lines. 



Transverse "«< ........ IQf lines. 



Second specimen : 

 Length of crown laterally, .---....- IJ inches. 

 Lateral diameter at base of crown, - - - - - - - -9 lines. 



Dr. Wyman* has described and figured the crown of a tooth of a Crocodile from 

 the Miocene, at Richmond, Virginia, which corresponds to the above descriptions, and 

 probably belongs to the same species. 



In relation to the specimens of the concavo-convex vertebrae, their size indicates a 

 species of crocodile probably no less than eighteen feet in length. 



One of the specimens represented in figure 4, I judge to be an anterior dorsal, 

 probably the second ; the other is a posterior dorsal, or a lumbar vertebra. 



In the former, the spinous process excepting its base, the transverse processes, the 

 articular or oblique processes excepting part of the right anterior and left posterior, 

 and the right anterior margin of the body, with the corresponding lateral tubercle, are 

 brolcen away. In form and general proportions, it bears a great resemblance to the 

 corresponding vertebra of the Crocodilus gangeticus, and the most striking difference 

 is observable in the spinal canal, which in the former is cordiform or trilateral with 

 rounded angles and the apex do\rn wards, while in the latter it is reversed. Judging 

 from its base, the inferior spinous process has been relatively thicker and not so broad 

 as in Crocodilus gangeticus or Alligator lucius. The junction of the body with the 

 neural arch is still indicated by suture in the specimen. The posterior convex head 

 of the body is hemispherical. The lateral tubercle for the head of the rib is formed 

 upon a relatively broad base. 



' Amer. Journ. of Science and Arts, Vol. x, 1850, p. 233, figs. 8a and 8b. 



35 



