1 INTR OB UCTION. 



The lowest vertebrate is the little Jmphioxus lanceolatus, usually assigned 

 to a distinct class, the Acrania. Between the Amphioxus and the Amphibia 

 are all the "^fishes," common and uncommon, including the Sharks and 

 Eays, and many for which there are no popular names. Likewise, between 

 the Amphibia and the Mammals are the classes Keptiles and Birds, no exam- 

 ples of which are herein considered. 



IV.— TERMINOLOGY. 



§ 22. Whoever does any systematic practical work in anatomy, whether by investi- 

 gation or teaching, is impelled, sooner or later, to suggest some modifications of the lan- 

 guage previously employed in recording or communicating observations and ideas. 



Such modifications are often put forth in publications without explanation or apology, 

 and their subsequent adoption by others may then depend less upon their intrinsic value, 

 than upon the reputation and authority of the proposers. 



In the following pages, especially in the account of the Brain, there will be found a 

 few new words, for the introduction of which reasons will be duly offered. 



Many other words and phrases will appear more or less unusual, some to one reader 

 and some to another. Those, however, who are most familiar with the best original 

 anatomical publications in not only their own language, but also those of other nations, 

 will, upon careful scrutiny, perceive that the present work really contains very few terms 

 for which there is not sound precedent in the writings of recognized authorities, in the 

 use of either the same words, or of words analogous in character and formation. 



From the productions of working anatomists in all parts of the world we have 

 endeavored to select, without bias or partiality, the terms which seem to us best suited to 

 the object, and most easily used. 



As a whole, therefore, the Terminology here employed is that of no one nation or 

 writer. Much less should it be regarded as our own, excepting in so far as we have 

 succeeded in our efforts to combine the elements from various sources into a consistent and 

 homogeneous whole. 



But while the prestige of authoritative precedent might lead us to make a personal 

 trial of any assemblage of terms, it would not, by itself, warrant an introduction into a 

 purely elementary work like the present. It is proper, therefore, to say that, %vith very 

 few exceptions, all of the names and descriptive terms here employed have withstood 

 the severe practical test of use by a large number of students for from one to seven 

 years. 



This test is called severe because these students have been comparatively mature, 

 and have done practical work in anatomy with the view of becoming either naturalists, 

 teachers or physicians ; and because they have not simply listened to lectures in which 

 the terms were used, but have been required to employ them in writing their own de- 

 scriptions of parts ; because, finally, they have been urged to make suggestions and criti- 

 cisms with entire freedom. 



On what, therefore, may be called experimental grounds, we feel justified in present- 

 ing this Revised Terminology of Anatomy to students other than our own ; but since 

 each year has brought about some change therein, we have no reason to think it perfect 

 or complete, and we ask the co-operation of all who may undertake to follow out our 

 directions with the view of rendering it better adapted to the needs of Practical Workers 

 in Anatomy. 



