310 REPORT—1846. 
pare,” Cuvier says, “the supraoccipital to the spinous processes which in 
certain animals originate by special points of ossification and remain for some 
time distinct from the rest of the vertebra: nevertheless, there is already here 
a great difference of structure and function*.” With regard to the points in 
which Cuvier is willing to admit an ‘ analogy’ between the occiput and the 
atlas, he subjoins, agreeably with his idea of the law which governed such 
correspondences,—“ These resemblances might naturally be expected in the 
part of the head placed at the extremity of the vertebral column, and the 
functions of which are, in fact, analogous to those of vertebra, since it gives 
passage, like them, to the great neural axis+.” 
With regard to the feature of resemblance (quelque rapport) which some 
had seen between the mastoid process and a transverse process, Cuvier founds 
his objection to its application to the vertebral character of the occipital 
bone on a false homology. Concluding that the mastoid in man (fig. 25, s) 
was homologous with the paroccipital in the hog (fig. 22, 4){ and some 
other quadrupeds, he deems the determination of the paroccipital as the 
transverse process of the occipital vertebra to be invalidated by the fact 
that the ‘ mastcid’ belongs, in man, not to the occipital but to the petrosal. 
There were cases, however, not unknown to the able Editors of the posthu- 
mous edition of the ‘Lecons d’Anatomie Comparée,’ where the true trans- 
verse processes of the occipital vertebra, though exogenous, like those of the 
succeeding trunk-vertebree in man, had become developed to an equal extent 
with such transverse processes ; the abnormality of the human occipital thus 
repeating its normal condition in the quadruped. They however do not cite 
these instances, or notice the confusion by their author of the true mastoid 
with the paroccipital in reference to this his first objection to the vertebral 
homology of the occipital segment. But it might further have been re- 
marked, in respect of the segment of the skull to which the mastoid really 
stands in parapophysial relation, that although the mastoid belongs in man to 
the petrosal in the sense of being anchylosed with it, it articulates with the 
parietal ; and the persistence or obliteration of a primitive suture is too vari- 
able a phenomenon to determine to which of two bones a third connected with 
both essentially belongs. The constant existence of the paroccipital either 
as an autogenous element or an exogenous transverse process in all the 
oviparous vertebrate classes, its common existence in mammals, and occa- 
sional, though rare, development in man, establish that additional, though 
by no means essential vertebral character in the occipital segment, which 
loidiens et les deux moitiés de l’anneau de V’atlas 4 la couvrir. Les condyles sont repré- 
sentés par les facettes articulaires au moyen desquelles l’atlas s’unit 4 axis. Le trou con- 
dylien qui laisse passer le nerf de la neuviéme pair, a quelque rapport avec le trou de l’atlas 
qui laisse passer le premier nerf cervical, et la premiére courbure de l’artere vertébrale. On 
a aussi trouvé quelque rapport entre l’apophyse mastoide qui, dans la plupart des animaux, 
appartient a l’occipital, et l’apophyse transverse de l’atlas et des autres vertébres; sur quoi 
il faut remarquer que ces rapports sont moindres dans l’homme 4 certains égards que dans 
les quadrupédes, puisque V’atlas n’y a ordinairement qu’une échancrure pour le passage de 
Vartére et que l’apophyse mastoide y’appartient entiérement au rocher.”—1. c. p. 710. 
* “Qn pourrait méme comparer l’occipital supérieur aux apophyses épineuses qui, dans 
certains animaux, naissent par des points d’ossification particuliers, et restent quelque temps 
distincts du reste de la vertébre; cependant il y aurait déja ici une grande différence de struc- 
ture et de fonction.” —/. c. p. 711. 
+ “Ces resemblances étaient naturelles 4 attendre dans la partie de la téte placéé a l’extré- 
mité de la colonne vertébrale, et dont les fonctions sont en effet analogues a celles des ver- 
tébres puisqu’elle laisse passer comme elles le grand tronc medullaire.”—. ¢. p. 711. i 
t Cuvier, e. g. describes this element as “ L’apophyse mastoide, qui est trés-longue, trés- 
pointue et ae de l’occipital,” in his elaborate Ossemens des Cochons, Oss. Fossiles, t. ii. 
pt. i. p. 117. 
