202 FOSSIL FISHES OF THE ENGLISH CHALK. 



unrecognised genus, Pseudocora.c. While ignorant, however, of the shape and 

 characters of the shark to which these teeth belong, it seems premature to 

 multiply generic names. 



Horizons and Localities. — Zone of Belemnitella rnucroiiata : Norwich. Zone of 

 Marsupites : Sussex (A. AV. Kowe). 



Qeims OXYRHINA, Agassiz. 



(?) Isurns, Rafiuesque, Caratt. Alcuni Nuovi Geueri, 1810, p. 11. 



Oxyrhina, L. Agassiz, Poiss. Foss., vol. iii, 1838, p. 86. 



Xenodolamia, J. Leicly, Jouru. Acad. Nat. Sc;i. Pliilad., [2] vol. viii, 18 77, p. 251. 



Generic Characters. — Teeth large, lanceolate in front of mouth, triangular and 

 much compressed at sides and in hinder part of jaws, without lateral denticles] 

 border of crown not serrated. 



Type Species. — An existing shark, Oxyrhina spallanzanii. 



Txemarlcs. — The species of this genus are widely distributed in existing seas. 

 Teeth occur in nearly all marine deposits of Upper Cretaceous and Tertiary age. 



1. Oxyrhina mantelli, Agassiz. Plate XLIII, figs. 10 — 15; Text-figures GO, 01. 



1822. Squalus zygcena (?), G. A. Mantell, Foss. South Downs, p. 227, pi. xxxii, figs. 4, 7, 8, 10, 11, 



26, 28. 



1839. Lamna mantelli, Gr. A. Mautell, Wonders of Geology, pp. 328, 426, ligu. 58, fig. 2. 



1843. Oxyrhina mantelli, L. Agassiz, Poiss. Foss., vol. iii, p. 280, pi. xxxiii, figs. 1 — 5, 7 — 9 (ncn 



fig. 6). 



1843. Lamna acuminata, L. Agassiz, torn, cit., p. 292, pi. xxxviia, fig. 54 (? non figs. 55 — 57). 



1850. Oxyrhina mantelli, F. Dixon, Geol. Sussex, pi. xxx, fig. 24. 



1850. Lamna acuminata, F. Dixon, ibid., pi. xxx, fig. 19. 



1873. Oxyrhina extenta, J. Leidy, Extinct Vert. Fauna W. Territ. (Rep. U.S. Geol. Surv. Territ., 



vol. i, pt. i), p. 302, pi. xviii, figs. 21 — 25. 



1889. Oxyrhina mantelli, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. -376, pi. xvii, figs. 9—21. 



1894. Oxyrhina mantelli, C. R. Eastman, Palseontogr., vol. xli, p. 149, pis. xvi — xviii. 



1902. Oxyrhina mantelli, M. Leriche, Ann. Soc. Geol. Nord, vol. xxxi, p. 116, pi. iii, figs. 49 — 53. 



Type. — Imperfect detached teeth from the Chalk of Sussex ; British Museum. 



Specific Characters. — A species of moderate size, the crown of the anterior teeth 

 usually not exceeding 3 cm. in height. Teeth rather stout; outer coronal face 

 always nearly flat, often with a few large vertical wrinkles ; inner coronal face 

 gently rounded; root short, the ])ranclies very divergent, thick, expanded, and 

 abbreviated. Anterior teeth large and comparatively broad, the crown only gently 

 curved outwards at the apex ; lateral teeth with the root nuich wider than the 

 main portion of the crown, which thus exhibits a sudden basal expansion ])ehind, 

 often also in front. 



