viii PREFACE. 
ventral. Medial refers to that side of the limb which in th 
normal position is toward the middle of the body; lateral t 
the outer side. Terms of direction which are derived only fror 
the structure of the limb itself are in some cases more conven 
ient than the usual ones. In the fore limbs the terms radi 
(referring to the side on which the radius lies) and ulna 
(referring to the side on which the ulna lies) are used; in th 
hind limbs the terms ial and fibular are used in a simila 
manner. Dzstal means toward the free end of a limb or othe 
projecting structure; proximal, toward the attached end. 
For all these terms an adverbial form ending in -ad ha 
been employed. Experience has shown this to be very usefi 
in practice, and while not expressly recommended by the BNA 
it is not condemned. Terms ending in -a@/ are therefor 
adjectives; those ending in -ad are adverbs. 
In compounding these terms of direction, the hyphen ha 
been omitted in accordance with the usage recommended b 
the Standard Dictionary. Thus dorsoventral is written i 
place of dorso-ventral, etc. The student will perhaps b 
assisted in understanding these compounds if he notes th 
the first component always ends in -o, so that the letter o prac 
tically serves the purpose of a hyphen in determining how th 
word is to be divided. 
In one particular the BNA nomenclature is not entirel 
consistent. While recommending or at least permitting th 
use of the general terms dorsal and ventral in place of th 
human posterior and anterior, and cranial and caudal in plac 
of supertor and inferzor, it retains the words anterior, posterior 
superior, and inferior as parts of the names of definite organ: 
For example, we have the muscle serratus anterior in plac 
of serratus ventralis; serratus posterior inferior in place « 
serratus dorsalis caudalis. This is very unfortunate, from 
comparative standpoint, but we have felt it necessary to retai 
the BNA terms in order that the structures of the cat ma 
receive the same names as the corresponding structures « 
man. 
In the matter of orthography we have endeavored to follo: 
the best English anatomical usage, as exemplified in Gray 
