452 A. S. Wooduward—British Jurassic Fishes. 
from the Oxford Clay of the neighbourhood of Peterborough a 
number of large bones of fibrous texture, and often of indefinite 
form, pertaining to some hitherto unknown extinct vertebrate. The 
_ flatter bones were considered by Mr. Hulke, in 1887, as not 
improbably referable to the dermal armature of a Dinosaur ;1 but, 
on visiting the collection in 1888, Prof. Marsh expressed the opinion 
that the remains were piscine, being unlike any of the numerous 
types of Dinosaurian dermal armour met with in America. At the 
beginning of the present year,? the writer of this note mentioned the 
possibility of these fossils indicating the presence of a large Acipen- 
seroid fish in the Upper Jurassic rocks; and it is proposed in the 
following pages briefly to discuss the few facts already available for 
consideration. One set of bones undoubtedly pertains to a single 
individual, and is thus of great value; but many of the fragments 
are scattered, and, if the interpretations now to be suggested prove 
correct, the axial skeleton of the trunk still remains to be dis- 
covered. No known specimens exhibit any traces of superficial 
ornamentation, and, though often massive, all the elements have the 
characteristic fibrous texture of fish-bone. 
The associated series of bones just mentioned was spread over an 
area of probably not less than twelve square yards, and the principal 
specimens may be enumerated and determined as follows: 
1. A large, oblong, flattened bone, of the kind already described 
by Mr. Hulke. It measures 2 ft. (0°61 m.) in length by 1 ft. din. 
(0°38 m.) in maximum breadth, is of a squamous character, thinning 
at each margin, and consists of two thin hard layers separated by 
a middle layer of soft diploé. In form and characters the bone is 
very suggestive of a frontal element. 
2. An elongated bone, 1 ft. 8in. (0°58m.) in length, somewhat 
broader at one extremity than at the other. One long margin is 
thickened and rounded, while the other is a thin edge; and the 
broader extremity is thicker than the narrower. This may perhaps 
be identified as angular. 
8. An elongated bone, 1 ft. 3in. (0°38 m.) in length, and the 
broader extremity of the corresponding element of the opposite side. 
This is probably the hyomandibular. The supposed upper extremity 
is somewhat expanded, and near this end on the posterior outer 
margin is a small facette, evidently for the operculum. For two- 
thirds of its width the bone is thick, but the anterior third is thin, 
as is also the inferior extremity. 
4. Portions of four long narrow bones, the largest being 2 ft. din. 
(0-785 m.) in length, and not more than 384in. (0-09 m.) in 
maximum width. Each bone is comparatively hard, irregularly 
~<-shaped in transverse section, and seems most nearly paralleled 
by the ossifications of the branchial arches in Teleosteans. 
5. A very large number of small, narrow, elongated bones of 
peculiar shape, probably to be regarded as giil-rakers. The largest 
1 J. W. Hulke, ‘‘Note on some Dinosaurian Remains in the Collection of A. 
Leeds, Esq.,” Quart. Journ. Geol. Soc., vol. xliii. (1887), p. 702. 
* Smith Woodward, ‘‘On the Paleontology of Sturgeons,’’? Proc. Geol. Assoc., 
vol. xi. (1889), p. 81. 
