274 REPORT—1846. 
All those bones which represent single vertebral elements are ‘ teleologi- 
cally 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, &c. for par- 
ticular offices. 
In the human skeleton, the clavicles, the (thoracic vertebral) ribs, are in- 
stances of simple and truly individual bones. The occiput, sphenoid, eth- 
moid, temporal, superior maxilla, mandible, hyoid, scapula, the so-called true 
vertebrae, the sacrum and coccyx, the sternum, and ossa innominata are 
‘homologically’ compound bones. 
The two parietals are essentially like the frontal and vomer, one ‘teleologi- 
cally’ compound bone : so, likewise, are the two nasals. And, if the view of 
the homology of the jointed filamentary skeleton of the rudimental ventral 
fin of the lepidosiren with the simple diverging appendages of the costal 
arches of the abdominal vertebrz be correct, then is not merely the mam- 
malian femur a teleologically compound bone, but the whole skeleton of the 
hind-limb from the femur to the distal phalanges inclusive must be regarded 
as representing the essentially single vertebral element, here called ‘diverging 
appendage, subdivided according to the law of vegetative repetition of centres; 
which law is progressively overruled and masked by-the supervention of the 
higher law of special modification and adaptation of such vegetative subdivi- 
sions to the exigences and habits and sphere of life of the species. 
In many animals all the parts of the skeleton of the limbs, and in all ani- 
mals some of the parts, are simple bones, in the sense of being developed 
from a single centre; but in none can they claim that essentially individual 
character which the clavicles and osseous parts of the ribs are entitled to, as 
being primary vertebral elements. 
To trace the mode and kind and extent of modification of the same ele- 
mentary parts of the typical segment throughout a large natural series of 
highly organized animals, like the vertebrata ; and to be thus led to appreciate 
how, without complete departure from the fundamental type, the species are 
adapted to their different offices in creation, brings us, as it were, into the 
secret counsels that have directed the organizing forces, and is one of the 
legitimate courses of inquiry by which we may be permitted to gain an in- 
sight into the law which has governed the successive introduction of ee ; 
forms of living beings into this planet. 
Vertebre of the Skull—Since it has been found that the bones of the trunk 
maintain through every kind and degree of adaptive modification, whether as 
‘thorax,’ ‘ carapace’ or ‘sacrum,’ an arrangement into segments in the con- 
stitution and relative position of the parts of which the vertebral type has been 
universally recognised—let us next examine, without bias, and, if possible, 
without reference to or recollection of previous attempts, in the first instance, 
whether such type be traceable through the remaining anterior part of the 
axis of the endo-skeleton, which, like the thorax and pelvis, has received, on 
account of its degree of coalescence and other modifications, the special col- 
lective term of ‘ skull ;)—or, whether nature has, in this part of the endo-ske- 
leton, so far departed from the pattern on which all the rest is constructed, 
that we cannot, without manifest violence to her arrangements, demonstrate 
the segmental composition ; or refer, without admitting modifications distinct 
in kind as well as degree from those that mark the vertebral character in the 
trunk, the constitution of such segments to the vertebral type. 
Taking the conical skull of an ordinary osseous fish—that of the cod (Mor- 
rhua vulgaris) for example,—if we detach the bones which form its hinder 
extremity, or base, and which immediately precede and join the atlas, from 
