[523] Proceedings of the Geological Society of London, vol. ii. p. 209.

Lign. 190. Mandible of Edaphodon Mantelli.
Chalk. Lewes. (1/2 nat. size.)

Lign. 191. Edaphodon leptognathus. 1/2 nat.
London Clay. Bracklesham.
The Upper and Lower Mandibles of the left side; viewed mesially or from within.

Fig.1.—The Upper Jaw; left ramus.
p m.—The premaxillary bone.
1, 2, 3.—The three dental tubercles.
2.—The Lower Jaw.

s.—The symphysial surface, by which this ramus is united
to the opposite or right side of the jaw.

4, 5, 6.—The three dental tubercles, or triturating surfaces,
of the left ramus of the lower jaw.

Many specimens, both of the upper and lower mandibles, have since been discovered in the Eocene beds, Chalk, Upper Greensand, Galt, Kimmeridge Clay, and Stonesfield Slate. The subject has been carefully investigated by Sir P. Egerton; and this eminent Ichthyologist has tabulated the principal forms, and arranged them under five genera.[524]