134 



DR. A. SMITH WOODWARD ON THE 



[May 1904. 



noticed that they exhibit a more decided obliquity, with a smaller 

 median elevation, than the corresponding teeth farther behind. 

 The transverse measurements (in millimetres) of the teeth of the 

 several series at the back of the symphysis are as follows : — 0, 8 ; 

 1, 6-5 ; 11, 5 ; in, 4 ; iv, 3 ; v, 2. 



The upper dentition of the right side is partly exposed from its 

 decayed attached face (PL XV. fig. 2, i'-vi'), partly seen from its oral 



Ptychodus deeurrens, Ag. ; oral aspect of the mandible of a small 

 variety or young individual, restored natural size ; from the 

 Lower Chalk of Glynde (Susse.v). 



aspect on a detached piece of chalk (fig. 3). The median row of 

 very small teeth is scarcely visible in the fragment just mentioned, 

 the large teeth of the first paired series being crushed together to 

 obscure it, but it is shown in back-view (fig. 3 a, 0'). Of the first 

 paired series (1') three teeth are preserved on the right and six on 

 the left side, all in natural sequence. They are about as large as 

 the teeth of the same series in the opposing jaw. The two or three 

 hindermost teeth (fig. 4) correspond with those ordinarily forming 



