200 FOSSIL FISHES OF THE ENGLISH CHALK. 



Text-fig. 59, and illustvatcs some of tlie variations wliicli occur in different parts 

 of the month. The npright tooth at the left-hand npper corner of the fignre is 

 specially noteworthy, being comparatively small and doubtless referable to the 

 anterior gap in the upper dental series. 



Horizons and Local! ties. — Universal, in all zones from that of Adinocamax 

 qiiadratus downwards. Also Upper Greensand and Cambridge Greensand. 



3. Corax jaekeli, A. S. Woodward. Plate XLIII, figs. 1—3. 



1895. Galeocerdo jaeJceli, A. S. Woodward, Ann. Mag. Nat. Hist. [6], vol. xv, p. 4, pi. i, figs. 5 — 7. 



Type. — Tooth; British Museum. 



Specific Gharacters. — Teeth comparatively small, very low and broad, with the 

 apex of the crown turned sharply backwards. Anterior border of crown gently 

 arched, with relatively large, though sometimes feebly marked, serrations in its 

 lower half; apex above posterior notch small and narrow; posterior border below 

 notch with seven to eleven coarse serrations, decreasing in size backwards. Root 

 with a slight median cleft for a nutritive foramen on its inner face. 



Description of Specimens. — The type specimen and the other two teeth of this 

 species originally described, were of uncertain origin ; but the three additional 

 specimens shown in PI. XLIII, figs. 1 — 3, were obtained by Dr. H. P. Blackmore 

 from the uppermost zones of the English Chalk. The shortest and deepest tooth 

 (fig. 1), which is probably referable to an anterior position in the jaw, has a 

 remarkably arched l)ase ; and the apical part of the crown is scarcely larger than 

 the uppermost of the eight denticles on its posterior border. Its anterior border, 

 Avhich is comparatively steep, is coarsely serrated in the lower half. The second 

 tooth (fig. 2) is less deep, with a relatively larger apical portion, and larger 

 anterior serrations. The base-line of its crown is less strongly arched, but the 

 stout root is still somewhat forked. The third tooth (fig. 3) is again less elevated, 

 with a wide extent along its arched root, and more numerous serrations on both 

 anterior and posterior borders. As already described, the type specimen exhibits 

 the slight median cleft on the inner face of its root where a nutritive foramen 

 enters. 



In the original description the teeth of this form were provisionally referred to 

 the genus Galeocerdo ; b\it Dr. Blackmore has kindly permitted the tooth shown 

 in fig. 1 to be cut across, so that its structure may be examined. This section 

 proves that the tooth is solid, and thus cannot belong to any genus of Carchariidae. 

 Its internal vaso-dentine resembles that of the Lamnidos and Notidanida? ; and it 

 is excluded from the latter family by the shnpe of the root. Among known 

 genera of Lamnidae the tooth can only be assigned to Gorax. 



