204 



FOSSIL FISHES OF THE ENGLISH CHALK. 



doubt as to their pertaining to Oxiirhivn, although their position in the jaw remains 

 uncertain. Eastman regards them as sjmphysial teetli. 



Teeth of O.ri/rhiiia occasionally exhibit small lateral denticles, and a few 

 examples may be noted in 0. manteUi. One anterior tooth (PI. XLIIT, fig. 11) 

 and a postero-lateral tooth (fig. 12) bear a single pointed denticle posteriorly, while 

 an apparently antero-lateral tooth (fig. L3) shows an indistinct crimping of the 

 slio-htly expanded base in front, with one separate denticle followed by some 

 crimping behind. There cannot be much doubt, indeed, that the small lateral 

 teeth named Lamna acuminata by Agassiz and Dixon, are really referable to 

 Oxyrh ina man felli. 



As already mentioned, portions of vertebral centra occur with the group of 

 teeth of this species from Grays, and are clearly similar to those described by 

 Eastman in the specimen from Kansas. Such vertebras are common in the Chalk, 

 and two specimens are shown, in upper view and vertical transverse sections 



Fig. G1. Oxyrltina mantelli, Agassiz ; upper anil lower dontitioii as restored by Dr. Charles R. Eastman, 

 miich reduced in size. Upper Cretaceous (Niobrara Group) ; Kansas, U.S.A. 



respectively, in PI. XLTII, figs. 11, 15. All the secondary calcifications within the 

 primitive double cone are radiating plates, which usually bifurcate towards the 

 periphery of the centrum. 



Horizons and Localities. — Universal, all zones from that of ActijiocauKW ([uad- 

 ratiis downwards. Also Upper Greensand and Cambridge Greensand. 



2. Oxyrhina angustidens, Reuss. Plate XLIIT, figs. IG — 20. 



1845. O.ryrJiina angustidens, A. E. Reuss, Verstein. bolim. Kreideform., pt. i, p. 6, pi. iii, figs. 7 — 13. 



1845. Oxyrldna acuminata, A. E. lleiiss, op. cit., pt. i, p. 7, pi. iii, figs. 17 — 19, pi. vii, tig. 20. 



1845. Oxyrhina heteromorpha, A. E. Eeuss, op. cit., pt. i, i>. 7, pi. iii, figs. 14 - 16. 



1846. Scoliodon priscus, A. E. E.9iiss, ojt. cit., pt. ii, p. 100, pi. xxiv, tigs. 23, 24, pi. xlii, figs. 10—12. 

 1889. Oxyrhina ancjustidens, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 380. 



1894. Oxyrhina ancjustidens, A. S. Woodward, Proe. Geol. Assoc, vol. xiii, p. 197, pi. v, tigs. 20 — 23. 



1902. Oxi/rhina angustidens, M. Leriehe, Auii. Soc. Geol. Nord, vol. xxxi, p. 117, pi. iii, figs. 59 — 05. 



)/l>e. — Detached teeth from the Cenomanian of Bohemia. 



