212 FOSSIL FISHES OF THE ENGLISH CHALK. 



which are not all parallel ; root prominent on the inner face, with a sharp median 

 groove. Anterior teeth without lateral denticles ; postero-lateral teeth with a 

 single pair of sharp denticles. 



Description of Specimens. — The teeth of this species are so delicate that the 

 root is often lost in the fossils, leaving isolated crowns in the same condition as in 

 the type specimens. They are easily recognised by the peculiar vertical striation 

 which covers the greater pai't of the inner coronal face (PL XLIV, fig. 15 a). 

 The sharp stria3 are closely arranged at the base, but many of them terminate at a 

 short distance upAvards, while those which persist diverge towards their upper end, 

 where they often admit other short intercalated striae. The crown in the anterior 

 teeth (PL XLIV, figs. 14, 15) is always sigmoidally bent, sometimes excessively 

 so (fig, IG). On the inner prominence of the root the nutritive foramen is inserted 

 in a groove. The hinder lateral teeth (fig. 17) are less elevated, with a pair of 

 very sharp lateral denticles ; in these the root projects strongly inwards, and also 

 shows the cleft for the nutritive foramen. 



Horizons and Localities. — Zone of Belemnifella mitcronata : Norwich. Zone of 

 Micrastcr corangulnmn : Greenhithe and Dover, Kent. Zone of Mlcraster cor- 

 testudinariiini : Purley, Surrey. Turonian zones : near Lewes and Amberley, 

 Sussex; Cuxton and Burham, Kent; Betchworth and Whyteleafe, Surrey. Zone 

 of ScliJoenharlila varlans : Dover. Undetermined zones : Guildford, Surrey ; War- 

 minster, Wiltshire. Also Upper Greensand, Cambridge Greensand, and Gault. 



2. Scapanorhynchus subulatus (Agassiz). Plate XLIV, figs. 18 — 21. 



1822. Siiimlus cornubicus, G. A. Maiitell (errore), Foss. South Downs, p. 22(5, pi. xxxii, fig. 1. 

 1843. Lamria (Odontaspis) suhulata, L. Agassiz, Poiss. Foss., vol. iii, p. 296, pi. xxxviia, figs. 5 — 7. 

 1889. Scapanorhynchus {f) suhulatiis, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 35G. 

 1894. Scapanorhynchus subulatus, A. S. Woodward, Proc. Geol. Assoc, vol. xiii, p. 196, pi. v, 



figs. 14, 15. 

 1902. Scapanorhynchus t (Odontaspis) subulatus, M. Leriche, Aim. Soc. Gtol. Nord, vol. xxxi, p. 107, 



pi. iii, figs. 5 — 7. 



Type. — Detached teeth from the Cenomanian of Saxony ; Palgeontological 

 Museum, Munich. 



Specific Characters. — Teeth usually smaller than in the preceding species. 

 Dental crown smooth on both faces, not wrinkled ; a single pair of acutely-pointed 

 lateral denticles well developed on all the teeth, those of the anterior teeth more 

 slender than those of the hinder teeth ; root })rominent on the inner face, Avith a 

 sharp median groove. 



Description of Specimens. — The typical teeth of this species are easily recognised 

 by their smooth, shining crown, with a straight base-line externally, from the ends 

 of Avliich rise the prominent lateral denticles. The outer aspect of an anterior 



