376 The American Naturalist. [May, 
halves, the ends are “dextran” and “sinistran,”® the direc- 
tion toward them “dextrad ” and “ sinistrad. ” d 
The intersection of the axis is as before “centrum,” the 
neighborhood “ central,” the direction “centrad.” All the 
parts lying in the imaginary plane passing through the prin- 
cipal and ventro-dorsal axis are “ median,” the neighborhood 
is “medial,” the more distant region on either side is “lat- 
eral.” The direction toward the median plane is “ mediad,” 
direction toward the’side is “laterad.” Medial does not 
appear to be any improvement upon Barclay’s term “ mesial” 
or Wilder’s modification “ mesal” for the same plane. The 
latter in fact is preferable both on account of prior use and 
brevity. The extreme outer lateral parts or surfaces are 
“dextran” and “sinistran” like the ends of the axis, the 
direction toward these “dextrad and “sinistrad.” Thus the 
two halves of the body are dextral and sinistral but the hands 
and feet are dextran and sinistran, the arms and legs extended 
dextrad and sinistrad of the dextran and sinistran surfaces of 
our bodies, and the right elbow is dextrad of the shoulder but 
mediad of the wrist. 
This statement according to Wilder and Gage should be 
that “the right elbow is distad of the shoulder but proximad 
of the wrist, ” mediad and mesal being restricted to the trunk 
or used only for the general statements with regard ua 
limbs. Usage derived from Barclay would apply proximal 
and distal wholly to the appendages, distal being toward the 
free end and proximal at or toward the attached end. Wilder 
and Gage use these terms in this restricted sense and Com- 
stock gives them an identical meaning. Butschli in the 
discussion quoted above in note also maintained that viet 
terms should be applied only to appendages and parts outs! 
of the mass of the body. That Schulze had no such ere 
tions in mind when framing his terms seems to be settled y 
his suggestion to use proximal as a synonym for central, sie 
®Wilder and Gage use the term “ aspect” in the same sense as Schulze words | 
AY oat ae 
. * i and ; 
ingin “an,” or Barclay's ending in “en”; thus there is the cephalic @ gir an 
ventral dorsal, lateral and sinistral aspects. The strongest objection Lid p require- a 
the fact that they are not mononymic, wher:as Scbulze’s terms fulfil this wo 
ment. 
