PLATE XVII. 



Figure 1. — Longitudinal microscopic section of the distal end of the 

 dental fang, from specimen No. 803. The small parallelogram, a-b, indi- 

 cates where the enlarged section shown in figure 2 was taken. There is 

 no pulp cavity, the interior of the tooth being composed of osteodentine 

 very similar in structure to that of the palatine. An obscure line occurs 

 near and parallel to the outer margin of the dentine. The fibers of the 

 dentine are at right angles to the outer surface of the tooth. 



Pig. 2. — A section of figuie 1 more highly magnified: e, the enamel; 

 c, the obscure dark line referred to above. In some places this line is 

 hardly visible. Since there seems to be no difference in the structure of 

 the dentine fiber.s at this point, it seems quite probable that it is caused 

 by some peculiarity of the fossilization. cl, dentine ; </, patches of dentine 

 in the osteodentine; v, blood vessel; /', bone cell cavity. 



Both of these figures were drawn by means of a camera lucida. 



