The Ornithosauria: An elementary study of the bones of Pterodactyles made from fossil remains found in the Cambridge Upper Greensand, and arranged in the Woodwardian Museum of the University of CambridgeSeeley, H. G. (Harry Govier)
Science
The Ornithosauria: An elementary study of the bones of Pterodactyles made from fossil remains found in the Cambridge Upper Greensand, and arranged in the Woodwardian Museum of the University of Cambridge
Seeley, H. G. (Harry Govier)
Pterosauria
The dorsal vertebræ with convex centra have all lost their neural
arches except No. 2. The form of the centrum is half a cylinder, as
long, or longer than wide, but sometimes depressed, and wider behind
than in front. The exterior surface is smooth, convex from side to
side, and slightly concave from front to back. The neural surface is
mesially excavated. Both anterior and posterior articular surfaces are
semicircular or sub-ovate, being wide from side to side.
The anterior articulation is cupped, concave from the neural to
the hæmal surface, and concave from side to side. The posterior
articulation is convex from the neural to the hæmal surface, in which
direction, it usually shows striations, and from side to side has a
gentle convexity, sometimes so slight as to be nearly flat.
The neural canal is large, ovate, and as high as is the centrum.
The neural arch is strong, compressed from back to front, and placed
as usual on the anterior part of the centrum. In outline it is
sub-rhomboid with the sides concave. There is a strong process on
each side above the neural canal for a rib, and apparently a neural
spine, but all are broken. The transverse processes for the ribs are
directed outward, and a little forward, flattened in front and behind,
the surfaces being sub-parallel, so that in front the neural arch
is concave from side to side. Behind, the neural spine is directed
between the transverse processes so as to over-hang the exposed part
of the superior surface of the centrum. At the points where the neural
spine bends back from the transverse processes are the posterior
zygapophyses, high above the neural canal, and parted from each other
by an interspace as wide as the canal is high. They look downward,
outward, and backward. The lateral surface below the transverse process
is narrow, flattened, bends at a right angle with the posterior
surface, rounds into the anterior surface, is a continuous curve with
the side of the centrum, and is concave from below upward. The superior
surfaces of the neural arch have the sides sub-parallel, they are
each concave from side to side; and these surfaces are excavated for
pneumatic foramina.
Dorsal vertebræ of the type with the centrum flattened closely resemble
cervical vertebræ with the centrum flattened, differing chiefly in the
less length of the centrum. Occasionally (as in No. 3) the neural arch
comes away from the body of the vertebra.
The centrum is very depressed, sub-quadrate, and wider than long;
the base is flat, or slightly concave, with occasionally a slight
longitudinal mesial ridge; the lateral outlines are concave, so that
the bone is pinched in from side to side. The neural surface of the
centrum is flat and parallel with the base, and, as usual, wider behind
than in front, but the centrum is not there so high. The surfaces for
the neural arch are flat, and extend nearly to the base of the centrum
in front, so that they look upward, outward and a little forward.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account