180 



REPORT — 1846. 



Theterm'presyhenoid'ipresphenoideum^SLt.o^gs. 3,5,20, 24, 25,&c.) is pro- 

 posed forthe'sphenoide anterieur,'on the principle of substituting, as the better 

 instrument of thought, a definite name for a descriptive phrase. For the same 

 reason 'postfrontal' (postfron- 

 tale, Lat., 12, 12, figs. 3, 5, 20, &c.) 

 is substituted for Cuvier's ' fron- 

 tal posterieur' and its synonyms. 

 The 'frontal' (frontale, Lat. 11, 

 figs. 3, 5, 20, &c.) and ' vomer' 

 (vomer, Lat., 13, figs. 4, 5, 20, 25), 

 are among the few bones which 

 have had their special homolo- 

 gies recognised unanimously 

 throughout the vertebrate sub- 

 kingdom ; in the one case even 

 without departure from the 

 original anthropotomical name, 

 and in the other, with but a 

 single deviation from the esta- 

 blished nomenclature. But when 

 Geoffroy was induced to reject 

 the term ' vomer' as being ap- 

 plicable only to the peculiar 

 form of the bone in a small 

 proportion of the vertebrata, he 

 appears not to have considered 

 that the old term, in its wider 

 application, would be used with- 

 out reference to its primary 

 allusion to the ploughshare, and 

 that becoming, as it has, a purely arbitrary term, it is superior and prefer- 

 able to any partially descriptive one. ' Rhinosphenal,' it is true, recalls the 

 idea of the vomer forming the continuation in the nasal segment of the skull 

 of the basi- and pre-sphenoidal series of bones in other segments ; but ' vomer,' 

 used arbitrarily, summons equally every idea derived to form the complex 

 whole from the general study of the bone throughout the vertebrate series. 

 ' Prefrontal' (prefro?itale, Lat., 14, 14, 

 figs. 4, 5, 21, &c.) claims the same pre- 

 ference over anterior frontal, and its 

 foreign equivalents, as does postfrontal 

 over its synonymous phrases. There is 

 also another reason for proposing the 

 term ; viz. because it is applied to bones 

 in the vertebrate series generally, accord- 

 ing to conclusions as to their homologi- 

 cal relations, which differ from those to 

 which Cuvier and Geoffroy had arrived. 

 The discussion of the discordant deno- 

 minations at present applied to this im- 

 portant element of the skull will be fully 

 carried out in the sequel. 'Nasal' 

 (iiasale, 15, figs. 4, 5, 21, &c.) is another 

 of the few instances in which it is possible to retain and generally apply an 

 old and received anthropotomical term. No one, it is presumed, will con- 



Disarticulated prosencephala or neuro-frontal arch, viewed 

 from behind: Cod-fish. 



Fig. 4. 



Disarticulated rhinencephalic, or neuro-nasal arch, 

 viewed from behind : Cod-fish. 



