198 



FOSSIL FISHKS OF THE ENGLISH CHALK. 



(\e Lehaie in the phosphatic chalk of Ciply, Belgium, exhibits some of the 

 variations which occur in different parts of the month (Text-fig. 58). A few of 

 the teeth from Maastricht differ from these in having the posterior border more 

 distinctly notched. 



The only English specimens which can be referred to this species are teeth 

 from the Upper Chalk of Norwich. The large tooth shown in PI. XLII, fig. 12, 

 is almost identical with certain teeth of G. filcafiis, except in si/e, and the original 

 of fig. 13 is perhaps also scarcely distinguishable; but the posterior teeth, figs. 14, 

 15, are more characteristic and there cannot be much doubt about their determi- 

 nation. 



ITorizon and Localifi/. — Zone of BeJemiilfcIla iimcvonaUt : Norwich. 





Fio. 58. Corax pristodontus, Agassiz; associated set of teeth, iiat. size. — Danian ; Cijsly, Belgium. 



B. M. no. P. .5827. 



2. Corax falcatus, Agassiz. PL XLII, figs. IG— 28; Text-figure 59. 



1822. S(puilns (jalens't, G. A. Mantell, Foss. South Downs, p. 227, pi. xxxii, figs. 12—16. 



1843. Corax faJcatm, L. Agassiz, Poiss. Foss., vol. iii, p. 226, pi. xxvi, fig. 14, pi. xxvi a, figs. 1 — 15. 



1850. Corax falcatus, F. Dixou, Geol. Sussex, pi. xxx, fig. 18. 



(?) 1850. Corax mnximus, F. Dixou, ibid., p. 366, pi. xxx, fig. 17. 



1889. Corax falcatus, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 424. 



1894. Corax falcatus, A. S. Woodward, Proc. Geol. Assoc, vol. xiii, p. 198, pi. vi, figs. 13 — 15. 



Tijije. — Detached teeth from the Chalk of Sussex ; British Museum. 



Specific Characters.SmaWev than the type species. Teeth more elevated, 

 with the anterior border usually less arched, the apex more attenuated, and 

 the posterior border more sharply notched; serrations distinct, except in very 

 small teeth, where they are sometimes feeble or perhaps absent. Root of teeth 

 Avithout any median cleft for a nutritive foramen on its inner face. 



Description of Specimens. — Three of the type specimens in the Mantell 

 Collection are re-figured in PI. XLII, figs. 16—18, and exhibit the characteristic 

 features of a sharp notch behind, a slightly curved border in front. The low- 



