Dr. T. Wright on the Paleontology of the Isle of Wight. 



widest part i \eeeds 1 inch, and its transverse diameter is T %ths 

 of an inch (d). 



The crown {d, b, c) is unequally convex in front and concave (a) 

 behind. The general form of the crown is shown in a, b, c, 

 the anterior side thereof (a, b) is convex and sabre-shaped, 

 and the posterior border («, b) is slightly concave ; the external 

 convex surface (b) is covered with smooth enamel, which forms 

 four blunt ridges on its most prominent part, and terminates 

 inferiorly in a delicate rugous structure, forming a well-de- 

 fined arch (b), the convexity of which is directed towards the 

 apex ; the posterior surface of the crown (a) is flat below and con- 

 cave above ; the enamel is smooth above and rugous below, as on 

 the anterior surface, but it extends much farther down the 

 crown (nearly half an inch) and forms an arch, the convexity of 



