ON THE VERTEBRATE SKELETON. 317 



precisely those of which the determination has been easiest, and respecting 

 the names and nature of which there has been the least discrepancy of opi- 

 nion. It is with pain and a reluctance, which only the cause of truth has 

 overcome, that I am compelled to notice the inconsistencies into which the 

 great Cuvier fell, when his judgement became warped by prejudices against 

 a theory, extravagantly and, perhaps, irritatingly, contended for by a con- 

 temporary and rival anatomist. After having established by the clearest 

 evidence and soundest reasoning in his great and immortal works that the 

 bones (7) in the fish (figs. 2 and 5) and reptiles (figs. 9, 10, 13, 19, 22) were 

 homologous with those in birds (7, figs. 8 and 23), mammals (7, figs. 1 2 and 

 24), and even in man (7, figs. 11 and 25); and, after contending that they 

 ought to bear the same name — under which, indeed, we find him describing 

 them in the ' Lecons d'Anatomie Comparee ' from man down to the fish — 

 Cuvier comes at last to declare that, in those animals in which they are 

 separated from the alisphenoids and mesencephalon, they are "particular 

 pieces which have a particular destination !" 



The relation of the mastoids (s, s), as parapophyses, to the parietal or 

 sphenoidal vertebra not having been detected in Cuvier's time, he supposes 

 that the pterygoids, in the system which makes a vertebra of the sphenoid, 

 can be compared to nothing else than the transverse processes of such. As, 

 according to my views, they are recognizable in General Homology as quite 

 distinct elements of another cranial vertebra, the arguments which Cuvier 

 advances in disproof of what he thought they must be called, do not concern 

 the subject of the present Report. The inferior exogenous processes, in- 

 deed, of the basisphenoid in mammals are not unlike those developed from 

 the under surface of the centrum of the atlas in Sudis gigas, or from some 

 of the cervical centrums in birds. .The argument founded by Cuvier on the 

 autogenous development of the true pterygoid (figs. 24- and 25, 24) would 

 weigh little against its parapophysial nature, if other characters concurred 

 to prove it a ' parapophysis ;' but its connections and position show it to be 

 a ' diverging appendage.' 



With respect to the anterior sphenoid, Cuvier affirms that its composition 

 is totally different from that of the posterior sphenoid and occipital, and from 

 that of any vertebra. By the term ' sphenoide anterieure ' is meant the 

 coalesced presphenoid and orbitosphenoids (figs. 24- and 25, 9 and io) ; and the 

 two bones referred to in the comparison signify, the one, the basi- and ali- 

 sphenoids (ib. 5 and 6), and the other the basi- and ex-occipitals (ib. 1 and 2). 

 With respect to 9 and 10, Cuvier remarks that it is never, in mammals, formed 

 of three pieces, but only of two ; and that these are properly the bony rings 

 for the optic nerves, which in course of time approximate and coalesce with 

 each other : but so long as the median suture divides them, no distinct or 

 third bony nucleus is developed in the intervening cartilage*. 



Since, however, we see that the homologues (recognised as such by Cuvier) 

 of the orbitosphenoids are something more than rings surrounding the optic 

 nerves in the bird (figs. 8 and 23, 10) and crocodile (figs. 9 and 22, s) — that 

 they are merely notched by the optic nerves, and are chiefly developed in 



* " L'on a voulu aussi considerer le sphenoide anterieur comme une vertebre dont les 

 frontaux completeraient la partie annulaire, et ou la position du trou spheno-orbitaire entre 

 les deux sphenoi'des repondrait assez aux trous inter-vertebraux ordinaires. Mais la compo- 

 sition du sphenoide anterieur lui-meme est toute differente de celle des deux os, dont nous 

 avons parle avant lui, et de celle d'aucune vertebre. Jl n'est jamais, dans les mammiferes, 

 forme de trois pieces, mais seulement de deux ; ce sont proprement des anneaux osseux pour 

 les nerfs optiques, qui par suite du temps se rapprochent et se soudent entre eux ; la suture 

 est toujours au milieu, et tant que l'ossification n'est pas complete, il n'y a entre les deux 

 anneaux que du cartilage, dans lequel il ne se forme pas de troisieme noyau." — /. c. p. 714. 



