11 
On a new Theory of the Skull and of the Skeleton; with 
a Catalogue of the Fossil Remains of Vertebrate 
Animals contained in the Woodwardian Museum. 
By H. Senuzy, F.G.8., Sidney Sussex College. . 
Tue author thought that it was not possible to discuss the 
theory of the Skull till the theory of the Vertebre had been 
determined; and that it was impossible to arrive at a theory 
of a vertebra without considering the theory of the growth 
of a simple ossification; and believed that when the theory 
of ossification was once arrived at, then the theory of the verte- 
bra, the theory of the skull, and the theory of limbs would 
follow from the conditions which determined the multiplication 
and co-ordination of simple bones. 
First, then, he endeavoured to show what the possible me- 
chanical forces acting upon bones were; and having discussed 
the source of these forces, concluded that all growth must be 
due to vibrations of pressure and tension; and that the intensity 
of growth depends on the amount of pressure and tension in the 
direction of the increase; and that the bones owe the origin of 
their first particle and form to the same causes which add to 
their bulk: illustrations of these views being drawn from Me- 
chanics, Pathology, and Comparative Anatomy. 
Secondly. ‘The nature of compound bones was considered, 
as illustrated by the comparative osteology of the humerus, and 
by the carapace of the turtle, and the so-called tarso-metatarsal 
bone of birds. And the author arrived at the conclusion that a 
primary ossification might, if the pressure and tension were 
sufficient, develope upon itself other ossifications or epiphyses 
in any direction; and that these epiphyses might themselves 
assume the nature of separate bones and also develope epiphyses: 
