It had hitherto been generally believed that the mode of ossification in the fowl was that which obtained in all birds - the ostrich and its allies (as L'Herminier, we have seen, had already shown) excepted.
Geoffroy here maintained that the five centres of ossification existed in the duck just as in the fowl, and that the real difference of the process lay in the period at which they made their appearance, a circumstance which, though virtually proved by the preparations Cuvier had used, had been by him overlooked or misinterpreted.
Detail, illustrating his statements by the preparations he exhibited, the progress of ossification in the sternum of the fowl and of the duck, pointing out how it differed in each, and giving his interpretation of the differences.
In their case the sternum begins to ossify from three very distinct points - one of which is the centre of ossification of Nitzsch's grouping.
These conditions are quite distinct from the normal process of ossification as is seen in bone.