The Baron Cuvier* at first inclined to a belief in the existence of these cranial vertebrae; but subsequently, and from no very clear reason, he expressed an opposite opinion, to which he adhered for the rest of his life. "But the fact that the head articulates to the spine by pieces, which resemble those which form the spine itself, constitutes no reason for saying that the head, in its totality, can be regarded as a developed vertebra. None of the parts of the head can be found, either in vestige or in germ, in any vertebra."*

Geoffroy St. Hilaire, one of the first and most zealous supporters of Scientific Comparative Anatomy in France, maintained, from an early period, the idea of the vertebral structure of the skull; he, however, recognised seven segments, each composed of nine pieces. But at the period when these discussions were going on, no settled opinions had been expressed as to the composition of a typical vertebra, and, so late as 1830, the learned Editor of Hildebrandt's Anatomy observes, speaking of Geof-froy St. Hilaire, "He carries his idea of a vertebra so far, that he regards the ribs, and the bones of the sternum which lie between the ends of the ribs, as portions of the thoracic vertebrae, "!

Had Oken abstained from the comparison of the upper and lower jaws to the thoracic and pelvic members, and of the teeth to the nails, the cause for which he laboured would have received more numerous supporters. His views of the composition of the cranial vertebrae were singularly clear, and remain, in great part, unchanged memorials to the present day of his genius. Every cranial vertebra, he said, consists of three pieces like the dorsal vertebrae; namely, of a body, and of two lateral arches which unite in a spine. In the cranium, the body of the occipital bone and the bodies of the two sphenoids (for there are two of them, even in the head of man,) correspond to the bodies of the dorsal vertebrae. The lateral parts of the cranial vertebrae are formed, for the first vertebra, by the two occipital pieces which support the condyles; for the second vertebra, by the two parietals {for the temporals do not enter into the construction of the cranium, they belong to the jaws); for the third vertebra by the two frontals. Lastly, for the face, there is still a vertebra; the body is formed by the vomer, and the spines by the two nasal bones.#

* Leçons d'Anatomie comparée, vol. ii., p. 712, 1837. t Hildebrandt's Anatomie, by Weber, t. ii., p. 133.

With these materials Professor Owen has followed up the investigation. Having determined the typical vertebra, and designated the elements which compose it by proper and significant names, he has succeeded in unravelling and referring to their proper typical positions the assemblage of bony pieces which constitute the skull. A system so perfect and so elaborately minute as that of Homological Anatomy, not only simplifies by its accuracy the study of the structure of the human frame, but it places within the reach of all the advantages derivable from the comparison of the anatomy of man with that of other animals by whom he is surrounded. If there be any one who thinks that such a system can be dispensed with in the study of Comparative Anatomy, I refer him to the best assemblage of anatomical facts which has hitherto been published in a collective form, namely, Cuvier's "Leçons d'Anatomie Comparée." He will, I think, come to the conclusion, that unless employed as a book of reference, it is well nigh useless to any one whose information is not nearly as great, and whose memory is not as tenacious, as that of the accomplished author.

* Isis, i., p. 551, 1820.