THE REGIONS OF THE LIMBS. 25 



tudiual line therein being called a middle or median line. But since certain 

 parts lie upon or cross this plane, and since it is sometimes desirable to 

 speak of lateral parts as more or less near it, Barclay proposed (A, 121) 

 for it the single word mesion. 



We have not met with this word in other writings, although mesial and 

 mesiad are not infrequent. 



Nevertheless, it seems desirable to designate this middle plane by a single 

 word which is at once significant, short and capable of inflection. 



Such a word is meson, from the Greek TO HKOOV, the middle, equivalent to 

 the more ponderous Latin meditullium. This word and its derivatives were 

 proposed (<>) by the senior author. 



For convenience, any point or line therein may be called meson, but the 

 lines most frequently referred to in description constitute the dorsal and 

 ventral borders of the plane, and may be known as dor si meson and ventri- 

 meson respectively. 



To avoid ambiguity, it would be well to employ mesal and its derivatives 

 only in reference to the meson ; intermediate (middle) may then be applied 

 to the second of any series of three similar parts ; while medial could be 

 used in reference to the digitus medius. 



44. Convenient additions to the vocabulary of toponymy would be terms of single 

 words, corresponding with meson, but indicating respectively the dorsal, ventral and other 

 aspects of the body. We refrain, however, from making any specific suggestion. 



45. Designation of the Regions of the Limbs. The body as a 

 whole, with the cat as with most vertebrates, consists of two general 

 divisions, axial and appendicular ; the former is the body proper or soma ; 

 the latter are the limbs or membra. 



On account of the approximately vertical position of the arms and legs 

 in the natural attitude of man, their attached and free ends had been called 

 superior and inferior, or upper and lower. 



For these terms, as inapplicable to the limbs of many animals (fishes and 

 turtles, etc.), as are the terms anterior and posterior (in the anthropic sense) 

 to the rest of their bodies, Barclay wisely substituted proximal and distal, 

 which have been very generally adopted. 



We speak, therefore, of the attached end of any appendage, as limb, ear, 

 barbel, tentacle, horn, spine, as the proximal end, its free or unattached 

 extremity being in like manner called distal. The same terms apply to the 

 corresponding ends of the segments, bones and muscles of these appendages. 



As has been well remarked by Mivart (2, 509), "The tail, to a 

 certain extent, partakes of the natures of both the trunk and the limbs. 

 It is like the limbs in that it is solid, that it contains no body-cavity, 

 and is not traversed by the alimentary canal." Still, the tail is really 

 a division of the soma, and its two ends should be designated as cephalic 

 and caudal. 



