CORAX. 



199 



crowned posterior tooth (fig. 17) may be compared with that of C. 2)rist<)do)ifus 

 (fig. 15), and the relative slenderness of its apical portion will be noted. Another 

 tooth with a gently excavated posterior border (fig. 19) is comparable with fig. 14, 

 and is evidently distingnishable by its greater height in proportion to its width. 

 The large tooth shown in fig. 20 corresponds closely with that of fig. 12, bat has a 

 less gibbous anterior border and a more attenuated apex. Another large notched 

 tooth (fig, 22) exhibits the characteristic elevation and apical slenderness ; and the 

 four smaller teeth from lower horizons in the Chalk, shown in figs. 23 — 26, are 

 also typical. A comparatively small upright tooth from Eastbourne (fig. 27) is 

 sharply notched near the base behind, and more gently notched in front. Its 



Fig. 59. Corax falcatus, Agassiz ; outlines of associated set of teeth, nat. size. — Upper Cretaceous (Niobrara 

 Group) ; Kansas, U.S.A. C. H. Sternberg Collection (B.M. no. P. 103-tG). 



outer face is exposed, and the root is shown to be slightly forked. A second 

 example, apparently of the same tooth, is exhibited from the inner face (fig. 28) 

 and shows that there is no median cleft for a nutritive foramen in the root. These 

 two small teeth may probably be referred to the anterior gap in the upper dental 

 series. 



The relatively large tooth from Houghton, Sussex, named Corax maximns by 

 Dixon, is imperfect at the base behind where the notch would occur (fig. 21). It 

 seems to be only a tooth of G. falcatus of unusual size. 



Teeth resembling those named Corax falcatus have an almost world-wide dis- 

 tribution in Upper Cretaceous deposits ; and in the Chalk of Kansas large groups 

 have ])een fouud associated with pieces of calcified cartilage and vertebral centra. 

 A selected series from one such group of naturally associated teeth is shown in 



