y indicative of homological relationships. Many bones,
single in the adult, arise from separate centres of ossification, but we
must distinguish between "those centres of ossification that have
homological relations, and those that have only teleological ones;
_i.e._, between the separate points of ossification of a human bone
which typify vertebral elements, often permanently distinct bones in the
lower animals; and the separate points which, without such
signification, facilitate the progress of osteogeny, and have for their
obvious final cause the well-being of the growing animal" (p. 105).
There is, for example, a teleological reason why in mammals and leaping
Amphibia (_e.g._, frogs), the long bones should ossify first at their
ends, for the brain is thus protected from concussion; in reptiles that
creep there is less danger of concussion, and the long bones ossify in
the middle (p. 105). But there is no teleological reason why the
coracoid process of the scapula should in all mammals develop from a
separate centre. The coracoid is however a real vertebral element
(haemapophysis), and in monotremes, birds and reptiles it is in the adult
a large and separate bone. Its ossification from a separate centre in
mammals has therefore a homological significance. The scapula in mammals
is an example of what Owen calls a "homologically compound" bone. All
those bones which are formed by a coalescence of parts answering to
distinct elements of the typical vertebra are "homologically compound"
(p. 105). On the other hand, "All those bones which represent single
vertebral elements are 'teleologically compound' when developed from
more than one centre, whether such centres subsequently coalesce, or
remain distinct, or even become the subject of individual adaptive
modifications, with special joints, muscles, etc., for particular
offices" (p. 106). The limb-skeleton, corresponding as it does to a
single bone of the archetype, is the typical example of a teleologically
compound bone. Owen in his definition of teleological compoundness has
combined two kinds of adaptation--(1) temporary adaptation of bones to
the exigencies of development, birth and growth (_e.g._, development of
long bones from separate centres); (2) definitive adaptation of a
skeletal part to the functions which it has to perform (_e.g._,
teleological structure of limbs). Such adaptations are, so to speak,
grafted on the archetype.

Owen's general views on the na