18 INTRODUCTION. 



vertebrae, cervical, thoracic, and lumbar, the most cephalic is the first ; so 

 too, in the normal position of the limbs (to be explained farther on), the 

 pollex and primus (great toe) are on the borders nearer the head, and may 

 sometimes be designated as the first digit and dactyl. 



In designating the fractional portions of the length of a bone, the 

 proximal half, third, fourth, fifth, etc., is the first ; the rest following in 

 order toward the distal end. 



When, however, the series embraces only two or three similar parts, the 

 general name for them all has been usually followed (in Latin) or preceded 

 (in Enghsh) by some word indicative of relative position ; as, e. g., processus 

 superior, and middle commissure. 



This plan effects a saving in the number of different words without the 

 risk of ambiguity, just as when we say John Smith senior, junior, and third. 

 But all such terms are open to the objection of being compound, and there- 

 fore incapable of inflection. 



In some cases, therefore, the more general terms have been combined 

 with the distinctive prefixes to form single words, like supraspinatus and 

 mesoglutcBus. Owen has also employed (A, III, 519) postcava and prcecava 

 and the senior author has proposed (33, 306) entopectoralis and ectopectoralis, 

 and, more recently {9 and 11), a series of similar names for parts of the 

 brain ; e. g., prcecommissura, medicommissura, postcommissura, etc. 



§ 31. The Limits of Terminological Change. — As has been stated 

 already, the modifications here proposed are intended to provide for what seem 

 to be actual necessities, irrespective of purely theoretical considerations, and 

 of any desire for a perfectly uniform and consistent terminology. It may bo 

 well, however, to specify certain general limitations to changes of anatomical 

 nomenclature. 



Priority is practically of little moment in respect to the names of organs, 

 since it is usually difficult to ascertain when and by whom they were first 

 applied. An example of this is aflEorded by the phrase foramen of Monro, 

 (Wilder, 3). Nor, indeed, has priority always been held sacred in systematic 

 zoology. Owen's " Deinosaurians " was proposed nine years later than vou 

 Meyer's "Pachypoda;" yet, as stated by Huxley (108, 33), it has been 

 retained, notwithstanding the small size of some members of the group. 



Etymological appropriateness is sometimes disregarded, as in the case 

 just mentioned, and in the more familiar names Reptiles, Vertelrates, 

 Edentates, etc. Prof. Huxley has recently expressed the common sense view 

 of the matter as follows : — 



"If well understood terms which have acquired a definite scientific 

 connotation are to be changed whenever advancing knowledge renders them 

 etymologically inappropriate, the nomenclature of taxonomy will before long 

 become hopelessly burdened." (C, 16.) 



So, too, the names of organs have sometimes been given in reference to 



