LEIDY ON BATHYGNATHUS BOEEALIS. 329 



melled crown has been about nine lines long by four in breadth at its base. The fang 

 of the tooth like that of the other ones is oval in section. 



The space between the first and second teeth represented in figure 1, appears to have 

 been occupied by another tooth, but its position is now filled with the red matrix of 

 the fossil. 



The second tooth seen in the figure is the largest and longest of the series : and its 

 enamelled crown when perfect was about an inch and three quarters long by seven 

 lines in breadth at the base. Its fang can be seen in the wide fissure of the jaw de- 

 scending two inches from the alveolar border ; and being broken it is observed to be 

 hollow as far as the enamelled crown. 



The crown of the third visible tooth has not fully protruded from the jaw ; and its 

 form and size appear to correspond closely with those that follow. 



The fourth, fifth and sixth teeth have very nearly the same size and form, and their 

 enamelled portion is three quarters of an inch in length by five lines in breadth at the 

 base. 



The space between the fourth and fifth teeth, occupied by matrix, is sufficiently 

 large to accommodate a tooth of the same size. 



The interval seen in the figure 1, between the sixth and seventh teeth, is sufficiently 

 large for two other teeth, and its posterior half is occupied by a tooth, the tip of which 

 has just appeared on a level with the alveolar margin. 



The seventh tooth represented in figure 1, is a little less than the two contiguous 

 preceding ones, and has the same form. Its enamelled crown is seven and a half 

 lines long by four and a half broad at base. 



Posterior to the latter tooth is the impression of another against the face of the 

 matrix of about the same size. 



From the extraordinary relative depth of the dental bone above described to its 

 length, and from its northern locality, I have proposed for the carnivorous lacertian 

 to which it belonged the name of Bathjgjiathus borealis* 



Was this animal probably not one of the bipeds, which made the so-called bird 

 tracks of the New Red Sandstone of the valley of the Connecticut ? 



This interesting fossil is the second authentic discovery of saurian bones in the New 

 Red Sandstone Formation of North America; the first being those found near Hassac's 

 Creek, in Lehigh Co., Pennsylvania, by Dr. Joel Y. Shelley, and described by my 

 friend Mr. Isaac Lea, under the name of Ckpsysaurus Pennsylvanicus.\ 



In relation to the exact locality and geological position of the Bathygnathus borealis, 

 Mr. J. W. Dawson has furnished me with the following note. 



" The fossil was found at New London, on the northern side of the Island, imbedded to the depth of nine 



* Proc. Acad. Nat. Sci., vi. 404. 



t Ibid, v., 171, 205 ; Journ. Ac. Nat. Sci. ii. 

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