220 report — 1S46. 



part which appertains to the sense-capsule, i. e. which is directly concerned 

 in the support of the membrane and cells of the olfactory organ. 



But leaving for the present the question of names, and returning to things, 

 let us pursue our search and comparisons of the bones which continue in the 

 higher classes to repeat the essential characters of those called ' prefrontals ' 

 in fishes. Were it necessary to add to the reasons above assigned for regarding 

 no. 14, fig. 13, as the homologues of 14 in the fish, notwithstanding they are 

 connate in the batrachian, I would cite the structure and relations of those 

 bones in the sword-fish. The whole of the anterior part of the extensive 

 interorbital space is occupied by the prefrontals, which join each other at the 

 median line by an extensive vertical cellular surface : they form the anterior 

 border of the orbit, and the posterior wall of the nasal fossa; they close the 

 cranial cavity anteriorly, and transmit the olfactory nerve to the capsule by 

 a central foramen. They are almost entirely covered by the frontals above, 

 which they support by a broad flat surface ; a very small portion only ap- 

 pearing on the upper surface of the skull at the anterior angle of the orbital 

 ridge. Were the frontals separated, the prefrontals would then appear, as in 

 the frog, at the median line : were the suture between the two prefrontals 

 to be obliterated in Xiphias, an ' os en ceinture' would be produced like that 

 of the frog. The nasal bone of the sword-fish, which Cuvier calls ' ethmoide,' 

 presents a cellular structure of its base, designed to break the force of the 

 concussion arising from the blow which is delivered by the ' sword.' But the 

 prefrontals manifest more extensively this peculiar cellular structure, which 

 Cuvier well says, 'Ton prendrait presque pour les cellules de l'ethmoide d'un 

 quadrupede*." 



Cuvier, not perceiving or not appreciating the grounds of the homology of 

 the 'os en ceinture' with the prefrontals, describes the divided nasal (15, fig. 

 13), in the batrachia as the ' frontaux anterieures' ; and reciprocally, having 

 called the bones in fishes, homologous with the bone 14, (which he thought 

 might represent the ethmoid in the frog) ' frontaux anterieures,' he gives the 

 name ' ethmoide ' to the bone 15, fig. 5, whether single or divided, in fishes. 

 It is not necessary to add anything to the arguments by which M. Agassiz 

 has sustained the conclusion of Spix, that Cuvier's ' ethmoid ' in fishes is the 

 ' nasal.' And it needs, I think, only to compare the connections of the 

 bones 15, fig. 13, with either the single or the divided nasals in fishes, and to 

 glance at the obvious homology of the bones h in Cuvier's pi. xxiv. fig. 1 — 6, 

 with the bones g g in figs. 4 & 6 of pi. xxvi. (' Ossemens Fossiles,' t. v. pt. 2), 

 to ensure the acceptance of the conclusion, that his ' frontaux anterieures ' 

 in the frog and the other anourans are the true nasal bones. 



In the python Cuvier transfers the name ' frontaux anterieures ' to the 

 lacrymal bones. The bones in this serpent, which are in neurapophysial 

 relation with the olfactory nerves, and which present other essential charac- 

 ters of the prefrontals (14) in fishes, are also two in number, in the form of 

 thin osseous plates, intervening on each side, anterior to the frontal, between 

 the vomerine and nasal bones, bent outwards in the form of a semicylinder 

 about the olfactory nerves, which they support and guide to the cartilaginous 

 capsule of the organ of smell, and having the palatine bones articulated to 

 their under and outer sides. The bones, which thus present every essential 

 character of the prefrontals, are those (s s in pi. ix. figs. 1, 2, 3, ' Regne 

 Animal,' t. iii. 1830) which Cuvier there calls 'cornets inferieures.' But 

 the true ' cornets ' (turbinals) are cartilaginous in serpents as in every other 

 reptile? and give attachment to the palatines in no animal. The bones b b in 



* Hist, des Poissons, t. viii. p. 194. 



