516 
ACTINOPTERYGTI. 
Genus OXYGNATHUS, Egerton. 
[Figs. & Descrips. Brit. Organic Remains (Mem. Geol. Surv.), 
dec. viii. 1855, no. 9.] 
Syn. Thrissonotus, L. Agassiz, Poiss. Eoss. vol. ii. pt. ii. 1844, p. 128 
(undefined). 
Cosmolepis, Sir P. Egerton, loc. cit. dec. ix. 1858, no. 1. 
Trunk elegantly fusiform, more or less elongated. Mandibular 
suspensorium oblique ; dentition consisting of a series of large, 
well-spaced conical teeth, and numerous minute teeth irregularly 
arranged and somewhat clustered ; cranial roof-bones finely tuber- 
culated, sometimes rugose, the facial bones and branchiostegal rays 
delicately striated, and the opercular bones almost smooth. Eins of 
moderate size or small, with very minute fulcra, the rays broad, 
distally bifurcating, and more or less covered with a very thin layer 
of ganoine; the rays of the pectoral fins, except the few short ones 
placed hindermost, articulated only at the distal extremities, all 
others uniformly articulated to the base. Dorsal and anal fins 
triangular in shape, somewhat longer than high, and the hinder rays 
very short; dorsal opposed to the space between the pelvic and 
anal fins; upper caudal lobe narrow and much attenuated, with 
small ridge-scales, the fin deeply forked and equilobate. Scales 
thick, small or of moderate size, very narrow ventrally, and orna¬ 
mented with delicate oblique lines of ganoine, in part bifurcating 
and branching, becoming very faint upon the anterior dorso-lateral 
region and partially subdivided into tubercles. 
p> * * 
Oxygnathus ornatus, Agassiz. 
1844. Thrissonotus colei, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 128 
(name only). 
1854. Oxygnathus ornatus, Sir P. Egerton, Ann. Mag. Nat. Hist. [2] 
vol. xiii. p. 435. 
1855. Oxygnathus ornatus, Sir P. Egerton, Figs. & Descrips. Brit. 
Organic Remains (Mem. Geol. Surv.), dec. viii. no. 9, pis. ix., ix.* 
1858. Thrissonotus colei , Sir P. Egerton, ibid. dec. ix. no. 2, pi. ii. 
[Fish wanting extremity of tail; British Museum.] 
1877. Oxygnathus ornatus, R. H. Traquair, Ganoid Fishes Brit. Garb. 
Form. (Pal. Soc.), pi. ii. figs. 2, 3. 
1890. Oxygnathus ornatus, A. S. Woodward, Ann. Mag. Nat. Hist. [6] 
vol. v. p. 432. 
Type. Fish wanting dorsal and caudal fins ; British Museum. 
The type species, attaining a length of about 0*4. Maximum 
