A 
ON THE VERTEBRATE SKELETON. 313 
“Now,” he urges, “vertebra properly so called give passage to the nerves only 
by the intervals that exist between them and the other vertebra, and not by 
particular foramina*.” Therefore the young anatomist must conclude that 
the dorsal vertebree of the ox, the abdominal vertebrz of the lophius, and 
every other segment of the trunk whose neural arches are directly perforated 
by the spinal nerves, are to be rejected from the vertebral category ! 
_ Ithas been shown in the generalities on the corporal vertebra (p. 265), that 
the neurapophyses in relation to the passage of their governing nerves may 
be either untouched, notched or perforated by them, without prejudice to 
their neurapophysial character. Viewed in the entire series of vertebrata 
the cranial neurapophyses are more frequently perforated than notched, those 
of the trunk more frequently untouched or notched by the nerves in passing 
through their interspaces. 
The penetration and sagacity of Cuvier nowhere shine forth more brightly 
than in his bold and true determination of the bone 6, fig. 5, in the cod-fish t 
as the homologue of the temporal wing of the sphenoid in the human skull. 
To any less-gifted comparative anatomist the relation would have been masked 
by the coalescence of the homologous part in man, by its connections with the 
squamosal and frontal, and its comparatively small proportions under the 
guise of a subordinate process; none of which characters exist in the ali- 
sphenoid of fishes: it still retains, however, in that class, as in man, its most 
essential connevtions in relation to the bones of its own segment and to the 
brain and nerves; and Cuvier availing himself of these in the determination 
of its special homology, was little likely to be swayed by so unimportant a 
variety as the transmission of the characteristic nerve by a foramen instead 
of by a notch. No sooner, however, has the time arrived and the call been 
sounded for an advance to a higher generalization, which includes and ex- 
plains the minor proposition, than Cuvier interposes the least important 
difference of the alisphenoid to check the progress. It will be obvious to 
the anatomist that the foregoing explanation of the value of the nerve- 
notch or hole in the homological character of a neurapophysis has been’ 
called forth by the weight of the name of the ebjector rather than by the 
force of the objection. 
. Cuvier directs his next argument against the vertebral character of the 
(neural arch of the) parietal segment generally. “Its composition,” he avers, 
“is different from that of other vertebra, since the ring (he had just before 
denied its annular form) would be composed of five pieces or even of six, inclu- 
ding the interparietal.” Yet Cuvier does not hesitate, in his Article V., ‘Les Ver- 
tébres’ (Ostéologie des Crocodiles), to reckon as the first vertebra, the atlas 
notwithstanding its composition of six pieces. 
_ If,indeed, Cuvier had subscribed to Geoffroy’s assertion, that “ Nature repro- 
duces the same number of elements, in the same relations, in each vertebra, 
only she varies indefinitely their form,’—his objection to the vertebral charac- 
ter of any given segment that might deviate from the assumed normal number 
of pieces would have been intelligible. But even, then, he would not have 
been guided consistently by his own principle; for the objection founded 
upon the supposed abnormal number of pieces in a cranial segment weighs 
' ¥* “ Ses ailes different beaucoup plus encore et des deux condyliens, et des deux piéces qui 
forment la partie annulaire des vertébres. A'la vérité, le trou ovale n’est quelquefois qu’une 
échancrure ; mais le plus souvent il est entouré d’os, et par conséquent un vrai trou. Il-en 
est de méme du trou rond toutes les fois qu’il est distinct du sphéno-orbitaire ; or les verté- 
bres proprement dites ne laissent passer les nerfs que par les intervalles qui existent entre 
elles et les autres vertébres, et non par des trous particuliers.”—/. c. p. 712. 
" F Régne Animal, 1817, pl. viii. fig. 2,0, p. 184. 
t “‘L’atlas est composé de six piéces qui, a ce qu’il paroit, demeurent pendent toute la vie 
distinctes.’’—Ossemens Fossiles, t. v. pt. ii. p. 95. 
1846. x5 
