18G FOSSIJ. FISHES OF THE ENGLISH CHALK. 



Ti/pr. — Pair of imperfect mandibular dental plates ; British Museum. 



Specific Characters. — Dental plates much resembling those of E. scdijirid-i, but 

 more slender and not attaining so large a size. 



Deiicrlptivn of Specimens. — The mandibular dental plates of the type specimen 

 display both the outer and the inner aspects, and have already been described and 

 figured by Agassiz and Newton, loc. cit. An exactly similar plate, only crushed in 

 the lower half of the symphysial region, is shown in PI. XLI, figs. 1, l<i. Its 

 prominent beak and very wide symphysial facette are well shown, and the arrange- 

 ment of the tritors is also seen. The median tritor (e.) is completely exposed, and 

 observed to be continuous to the symphysis. The palatine dental plate is associated 

 with a mandibular pair from Lewes, described by E. T. Newton, loc. cit. It differs 

 from that of E. sedgwicld in being more slender, with the tritors longer and 

 narrower. 



A right mandibular dental plate from Glynde in the Willett Collection, 

 Brighton Museum (No. 1-13), exhibits the median tritor subdivided into several 

 portions, but seems to represent only a variety of E. mantelli (E. T. Newton, lor. 

 cit., p. 17, pi. iv, fig. 10). 



Horizons and Localities. — Turonian zones : neighbourhood of Lewes and 

 Houghton, Sussex. Zone of Bolaster salxjlohosns : Glynde and Clayton, Sussex ; 

 Burham, Kent. Zone of Schlocnhachia varians ; Dover, Kent. Undetermined 

 zones : Brighton, Sussex ; Guildford, Surrey. 



3. Edaphodon agassizi (Buckland). Plate XLI, fig. 2. 



1835-36. Chinuvm MjassizK, W. Buckland, Proc. Geol. Soc, vol. ii, j). 20(3, aud Phil. Mag. [o], 



vol. viii, p. 5. 

 1843. Ischyodiis agassizi, P. M. Gf. Egertou, Proc. G-aol. S.)e., vol. iv, p. 1.56. 



1843. Ckumvra {larhyodon) agassizii, L. Agassiz, Poiss. Foss., vol. iii, p. 341, pi. xla, figs. 3, 4 (? 5) , 

 pi. xlc, fig. 16 {non figs. 14, 15). 



1844. CUmxra, Gr. A. Maiitell, Medals of Creation, p. 621. 



1878. Edapliodon agassizii, E. T. Newton, Chimseroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv.), 



p. 12, pi. iii. 

 1891. Edaphodon agassizi, A. S. Woodward, Catal. Foss. Fishes B. M., pt. ii, p. 77. 



Tijjpe. — Imperfect mandibular tooth ; British Museum. 



Specific Characters. — Mandibular dental plate comparatively short and stout, 

 and the beak only slightly produced ; symphysial facette scarcely occupying one- 

 third of the inner aspect ; beak-tritor composed of a series of lamina3, the other 

 tritors consisting of numerous tubules ; median tritor very broad, occupying the 

 greater portion of the oral surface, and apparently exposed above throughout 

 its length. 



Description of Specimens. — The type specimen is so much broken along its 



