OXYRHINA. 



203 



Descri2Jtion of S'pecimeus. — The type specimens in the Maiitell Collection are 

 detached anterior teeth, mostly imperfect, but an associated set of over fifty teeth, 

 found with vertebrae in the Upper Chalk of Grays, displays the principal characters 

 of the whole dentition of the species. Thirteen of these teeth are shown of the 

 natural size in the accompanying Text-fig. 60, representing various parts of the 

 mouth. Some anterior teeth are narrower and more lanceolate than the foremost 

 here seen, while some of the posterior teeth are still smaller than the two low- 



FiG. 60. Oxyrliina mantelli, Agnssiz; associated set of teeth, nat. size. — Zone of Micraster corangiiimi.in ; 

 Grays, Essex. Bowerbank Collection (B. M. nos. 32347, 39434). 



crowned specimens at the end of this selected series. The vertical wrinkles in the 

 basal half of the outer face of the crown are indicated in five of the drawings. 



An associated set of nearly three hundred teeth evidently of the same species, 

 from the Niobrara Chalk of Kansas, U.S.A., has been studied by Eastman (1894), 

 who considers that they were probably arranged in the jaws as shown in the 

 diagram, Text-fig. 61. With these normal teeth in the Kansas specimen there are 

 also eleven very small distoi-ted teeth Avith a root as squat as that of the English 

 Chalk fossil represented in PI. XLIII, fig. 10. Such teeth were originally 

 described by Leidy under the name of Xenodolamia, but there can be no longer any 



