membrane that can be imagined,
in the interstice between them, reaching from their root or joint on the
back up above the hinder part of the head, and near half-way their own
length; but when closed, the membrane falls down in the middle upon the
neck, like a handkerchief. There are also two other ribs rising as it
were from the same root, which, when open, run horizontally, but not so
long as the others. These are filled up in the interstice between them
and the upper ones with the same membrane; and on the lower side of
this is also a deep flap of the membrane, so that the arms can be either
above or below it in flight, and are always above it when closed. This
last rib, when shut, flaps under the upper one, and also falls down with
it before to the waist, but is not joined to the ribs below. Along the
whole spine-bone runs a strong, flat, broad, grisly cartilage, to which
are joined several other of these ribs; all which open horizontally, and
are filled in the interstices with the above membrane, and are jointed
to the ribs of the person just where the plane of the back begins to
turn towards the breast and belly; and, when shut, wrap the body round
to the joints on the contrary side, folding neatly one side over the
other. At the lower spine are two more ribs, extended horizontally when
open, jointed again to the hips, and long enough to meet the joint on
the contrary side cross the belly; and from the hip-joint, which is on
the outermost edge of the hip-bone, runs a pliable cartilage quite down
the outside of the thigh and leg to the ankle; from which there branch
out divers other ribs horizontally also when open, but when closed, they
encompass the whole thigh and leg, rolling inwards cross the back of
the leg and thigh till they reach and just cover the cartilage. The
interstices of these are also filled up with the same membrane. From the
two ribs which join to the lower spine-bone, there hangs down a sort
of short apron, very full of plaits, from hip-joint to hip-joint, and
reaches below the buttocks, half-way or more to the hams. This has also
several small limber ribs in it. Just upon the lower spine-joint, and
above the apron, as I call it, there are two other long branches, which,
when close, extend upon the back from the point they join at below to
the shoulders, where each rib has a clasper, which reaching over the
shoulders, just under the fold of the uppermost branch or ribs, hold
up the two ribs flat t