ON FOSSIL FISH-TEETH. 303 



much more acute (nearly a right) angle at which the two portions of the 

 inner margin of the tooth met, and in the more closely adjoined horns 

 or ridges. It is from the Lettenkohle of Hoheneck (Triassic.^Upper 

 Muschelkalk of Thuringia;. 



The species is dedicated to the Revd. S. Hislop of Nagpur, one of the 

 most successful cultivators of Geology in India and author of some most 

 valuable papers on the structure of that district. 



Found in ferruginous clayey beds near Maledi, 150 miles S. S. W, 

 from Nagpur. 



Ceeatodus Hunterianus. n. s. 

 PL xv._ Figs. 1—6. PI. xvi. Fig. 4. 

 This species is at once distinguished from all figured Ceratodi by the 

 strongly marked, and greatly elevated ridge which bounds its internal 

 border or edge, and which gives it so peculiar a form. The inner edge 

 of the tooth is greatly curved, the larger and anterior portion being 

 about one-third longer than the posterior. These two portions form an 

 obtuse angle (about 125°^ at the points of meeting, this angle marking 

 also the highest or culminating point of the interior ridge of the tooth. 

 This ridce or raised edge of the tooth is here so marked that its total 

 height from the surface of the osseous layer is double the total height 

 of the horns or ridges at the other edge of the tooth. In general outline, 

 (looking down on the tooth) the form is an obtuse scalene curved-sided 

 triangle the base or longest side being formed by an imaginary line 

 joining the points of the horns or projections. The anterior portion of 

 the smooth internal edge is slightly and continuously curved, and is 

 considerably longer than the posterior portion, the latter is also 

 curved. In profile, this variety diflers materially from C. His- 

 lopianus. The edge rises suddenly from the posterior horn (PI. sv. 

 Fig. 2 ; PI. xvi. Fig. 4) to nearly its greatest height and con- 

 tinues to form a most prominent ridge to the point of the curve or 



