208 FOSSIL FISHES OF THE ENGLISH CHALK. 



first specimen there are also some of tlic very small hindmost teeth withont lateral 

 denticles. 



Some teeth Avitli nearly npright crowns (PI. XLIV, figs. 3, 4) are less shar])ly 

 pointed than those in the two gronps jnst mentioned. An accessory pair of 

 minnte onter cnsps is extremely rare (fig. 5). The larger teeth (fig. 6) are very 

 stout, but usually exhibit all the peculiar features of the species. A few of them 

 (fig. 7) are wrinkled on the outer face almost as much as in L. snlrafa, and one 

 tooth figured by Dixon {op. clt., pi. xxxi, fig. 17) makes a close approximation to 

 the front teeth of the latter species. 



Horizons and LocaUties. — Universal, all zones. Also Upper Greensand, 

 Cambridge Greensand, and Gault. 



2. Lamna arcuata, A. S. Woodward. Plate XLIV, figs. 8, 9. 



Ifi94. Lamna arcvata, A. S. Woodward, Proc. Geol. Assoc, vol. xiii, p. 198, pi. vi, fig. 10. 

 1897. Lamna arcvata, F. Prieui, Bull. Soc. Geol. France, [3] vol. xxv, p. 42, pi. i, figs. 10, 11. 



T//pc. — Tooth from zone of BelcnuiUeUa mnryoiKita ; Bi-itish Museum. 



Specific Characters. — Crown of teeth comparatively slender, narrow, and acute, 

 moderately compi'essed, smooth, and somewhat bent in the principal lateral teeth ; 

 a single pair of large acuminate lateral denticles ; root small, but forming a 

 considerable inward prominence without any groove for the nutritive foramen. 



Description of Spcciuunis. — The type tooth is shown from the outer and lateral 

 aspects in PL XLIV, figs. 8, d>a, and is probably referable to the middle of the 

 side of the jaw. The enamel of the crown and denticles is completely smooth. 

 The inner prominence of the root has a flattened lower face. A second specimen 

 (figs. 9, 9 a) is more slender, with a less deepened root. 



Horizon and Locality. — Zone of Bclemnitella mncroiiata : X^orwich. 



3. Lamna semiplicata (Agassi/). Plate XLIV, figs. 10, 11. 



1843. Otodus sevtijdicahis, L. Agassiz (e.r Minister, MS.), Poiss. Foss., vol. iii, p. 272, pi. xxxvi, 

 fig. 32 (? fig. 33). 



1888. Otudus semiplicatus, A. S. Woodward, Proc. Geol. Assoc, vol. x, p. 292. 



1889. Lumna semii)licata, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 397. 



1894. Lamna semij'licala, A. S. Woodward, Proc. Geol. Assoc, vol. xiii, p. 197, pi. vi, figs. 3, 4. 

 1902. Otodus semiplicatiis, M. Lericlie, Ami. Soc. Gc'ol. Nord, vol. xxxi, p. 114, pi. iii, fig. 48. 



Ti/pc. — Base of tooth from the Cenomanian of Saxony ; Paleeontological 

 Museum, Munich. 



S])ccifir Gliaractcrs. — Teeth robust, of large size, the crown sometimes 3 cm. 

 in height. Outer coronal face even, flat or slightly convex ; a series of short 



