_Nomenclature._--The question of nomenclature has been one of difficulty. What is desired is a _uniform_ set of anatomical names,--a system that shall be generally used by anatomists. At present the greatest diversity prevails as to the names to be applied to the different structures of the body. The only set of terms which at the present time seems to have any chance of general acceptance is that proposed by the German Anatomical Society at their meeting in Basel in 1895, and generally designated by the abbreviation BNA. This system has therefore been adopted, in its main features, for use in the present work. It seems impossible at the present time, however, to impose any one set of terms absolutely upon anatomists of all nations, and we have felt it necessary to use for certain familiar structures, in place of the BNA terms, names that have come to have a fixed place in English anatomy, and may almost be considered component parts of the English language. The German anatomists have expressly recognized the fact that this would be to a greater or less degree necessary among anatomists of different nations, and have characterized their list as for the present tentative, and capable of farther development. The only purpose of a name is that it shall furnish a key to a common understanding; where the BNA name does not furnish such a key to English readers, and where there is a term in established English usage that does serve this purpose and seems unlikely to be supplanted, we have used the latter. But we have endeavored to make the number of these exceptions as small as possible, and in such cases we have usually cited at the same time the term proposed by the German society, followed by the abbreviation BNA. When, on the other hand, we have adopted a BNA term for which there is also a commonly used English equivalent, the latter has likewise usually been cited in parenthesis.
In deciding whether or not to use in a given case the BNA term many difficult cases arose. Will the common English name _innominate_ bone (os innominatum) be replaced by the BNA term _os coxæ_ or _coxal bone_? We have held this to be highly improbable, and have therefore used the term _innominate bone_, merely citing _os coxæ_ (BNA) as a synonym. In the same way we have used _centrum_ as a designation of a part of a vertebra, in place of _corpus_ (BNA); _premaxillary_ bone or _premaxilla_ in place of _os incisivum_ (BNA); _malar_ bone in place of _os zygomaticum_ (BNA); _trapezoid_ as a name of one of the bones of the carpus, in place of _os multangulum minus_ (BNA), etc. In other cases where it has seemed probable that the BNA term would come into common use, though now unfamiliar, this and the more common English expression are both used or used alternatively; such has been the case, for example, with the Gasserian ganglion or semilunar ganglion (BNA). In naming the cerebral sulci and gyri the system in use for man is not well fitted for bringing out the plan of those in the brain of the cat, so that it was necessary to reject the BNA names for these structures.