392 
CROSSOPTERYGII. 
Genus ONYCHODUS, Newberry. 
[Bull. National Institute, 1857, p. 5.] 
External bones and scales ornamented with tuberculations, more 
or less conical and radiately grooved. Clavicle triangular in shape, 
with relatively large inferior limb; infraclavicle without an elon- 
gated ascending process. Presymphysial bone very prominent, its 
teeth much larger than those of the dentary. 
Onychodus sigmoides, Newberry. 
1857. Onychodus sigmoides , J. S. Newberry, Bull. National Inst. p. 5. 
1862. Onychodus hopkinsi, J. S. Newberry (errore), Amer. Joiirn. Sci. 
[2] vol. xxxiv. p. 77, woodc. fig. 3. 
1873. Onychodus sigmoides, J. S. Newberry, Rep. Geol. Surv. Ohio, 
vol. i. pt. ii. p. 299, pi. xxvi. figs. 1-5, pi. xxvii. figs. 1, 2. 
1889. Onychodus sigmoides, J. S. Newberry, Pakeoz. Fishes N. America 
(Mon. U.S. Geol. Surv. no. xvi.), p. 56, pi. xxxvi. figs. 1-4, 
pi. xxxvii. figs. 1-10. 
Type. Portions of mandible ; Columbia College, New York. 
The type species of large size, the longest presymphysial teeth 
measuring 0‘058 in length. Tuberculations upon scales conical and 
prominent^ sculptured, those upon the external bones rounder, 
somewhat smoother, and more numerous. Dentary teeth regular 
in size and shape throughout the greater part of the thickened oral 
border, each tumid in its basal half and tapering to the very slender 
enamelled apical portion; presymphysial teeth sigmoidally curved, 
stout, with a large central cavity, nearly regular in size, and loosely 
attached to the supporting bone. 
Several detached bones of this species, in the Museum of Colum¬ 
bia College, New York, are figured by Newberry, op. eit., 1889. 
Form, df Log. Corniferous Limestone (Lower Devonian) : Ohio. 
Not represented in the Collection, Id .Jtfesrry% 
Onychodus anglicus, A. S. Woodward. 
[Plate XY. fig. 1.] 
1888. Onychodus anglicus, A. S. Woodward, Geol. Mag. [3] vol. v. 
p. 500, woodc. 
Type. Presymphysial bone ; Oxford Museum. 
A very small species, known only by the presymphysial bone, 
which is remarkably in-rolled in the form of a scroll at its inferior 
extremity. Presymphysial teeth tumid in the basal half, much 
