especially in the case of the limbs and vertebral column, what is
called metameric segmentation, that is, a repetition of parts, one
behind the other, along the axis of the body. Thus the bodies and
arches of the vertebrae repeat each other, and so do the spinal
nerves. The renal organ of the rabbit, some time before birth,
displays a metameric arrangement of its parts; but this disappears,
as development proceeds, into the compact kidney of the adult. But
the metameric segmentation in the rabbit's organism is not nearly so
marked as that of an earthworm, for instance, which is visibly a
chain of rings. If the student wants a perfect figure of metameric
segmentation he should think of a train of precisely similar
carriages, or a string of beads. One bead, one carriage, one
vertebra, would be a metamere.