184. FOSSIL FISHES OF THE ENGLISH CHALK. 
1850. Hdaphodon sedqwicki, F. Dixon, Geol. Sussex, p. 203. 
1864. Edaphodon hualeyi, H. G. Seeley, Ann. Mag. Nat. Hist. [3], vol. xiv, p. 276 [mame only]. 
1878. Edaphodon sedqwickii, E.'T. Newton, Chimeroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv., 
Mon. iv), p. 7, pls. i, ii. 
1891. Edaphodon sedqwicki, A. S. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 73. 
Type.—Imperfect right mandibular dental plate from the Cambridge Green- 
sand ; Geological Society of London. 
Fic. 58. Edaphodon sedgwicki, Agassiz ; left vomerine 
dental plate, inner side view, two thirds nat. size.— 
Cambridge Greensand. b., posterior end of oral 
margin; c., d., post-oral margin; m. art., surface 
articulating with palatine plate ; sym., symphysis; 
1—6, tritors. After KE. 'T. Newton. Fia. 54. Edaphodon sedgwicki, Agassiz; left palatine 
dental plate, oral view, two thirds nat. size-—Chalk, 
Lewes. a., b., anterior and posterior inner tritors ; 
c., outer tritor ; d.,e., inner or symphysial margin ; 
e., f., posterior margin; f., g., post-oral margin; 
g., h., outer or oral margin. After E. T. Newton. 
Pia. 55. Edaphodon sedgwicki, Agassiz; left mandibular dental plate, inner or oral view, two thirds nat. 
size.—Chalk, Lewes. a., beak with tritor; b., symphysial tritor; c., d., anterior and posterior outer 
tritors ; e., median tritor; a.,b.,h., f., symphysial surface; d., g., post-oral margin. After E.T. Newton. 
Specific Characters—The largest species from the Chalk, the mandibular 
dental plate sometimes measuring 20 cm. in length. Mandibular plate with a 
very prominent beak, and the symphysial facette occupying at least one third of 
