ON THE VERTEBRATE SKELETON. 313 



" Now," he urges, "vertebrae properly so called give passage to the nerves only 

 by the intervals that exist between them and the other vertebrae, and not by 

 particular foramina*." Therefore the young anatomist must conclude that 

 the dorsal vertebrae of the ox, the abdominal vertebras 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 ! 



It has been shown in the generalities on the corporal vertebrae (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 f 

 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 connections 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 objector 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 vertebrae, 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., l Les Ver- 

 tebres ' (Osteologie des Crocodiles) J, 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 pieces qui 

 forment la partie annulaire des vertebres. A' la verite, le trou ovale n'est qnelquefois qu'une 

 echancrure ; mais le plus souvent il est entoure d'os, et par consequent un vrai trou. II en 

 est de meme du trou rond toutes les fois qu'il est distinct du spheno-orbitaire ; or les verte- 

 bres proprement dites ne laissent passer les nerfs que par les intervalles qui existent entre 

 elles et les autres vertebres, et non par des trous particuliers." — I. c. p. 712. 



t Regne Animal, 1817. pi. viii. fig. 2, o, p. 184. 



+ "L'atlas est compose de six pieces qui, a ce qu'il paroit, demeurent pendent toute la vie 

 distinctes." — Ossemens Fossiles, t. v. pt. ii. p. 95. 



1846. y 



