19.4 Thomas Nomenclature of Measurements. 



the English word basal by the older writers, such as Flower and 

 others, who used the measurement from the gnathion; while 

 basilar is an adaptation of the German of Hensel and his school, 

 who used the ' ' basilar-ldnge ' ' from the henselion . These 

 names again, combined with condylo-, readily express the points 

 which are used by those who like to adopt the condylioii as a 

 posterior measuring point. 



But further, the association of the ending " al " with a meas 

 urement from the gnathion, and " ilar " with one from the 

 henselion, if once defined and fixed, may be utilized in a second 

 case of similar character. 



The length of the bony palate is a measurement given by all 

 careful describers, but the anterior measuring point used is again 

 either the gnathion or henselion, doubt as to which is being 

 used often nullifying the value of the measurement altogether.* 

 To avoid this doubt I would suggest, exactly as in the other 

 case, that the name of the measurement from the gnathion 

 should end in " al " and that from the henselion in "ilar." 

 We should then have: 



PALATAL LENGTH, the distance from gnathion to palation. 



PALATILAR LENGTH, the distance from henselion to palation . 



The indeterminate ' ' palate length ' ' would then be dropped 

 altogether. 



II. THE NAMES OF THE CHEEK-TEETH OF MAMMALS. 



Although the cheek-teeth of mammals, the molars and pre- 

 molars, have been studied and written about ever since the birth 

 of zoology, no uniform system of naming them has been evolved 

 and there is the greatest divergence between the usage of differ 

 ent workers on the subject. In old days all were called molars 

 or grinders; then the premolars were distinguished from the 

 true molars (although French zoologists, Winge in Denmark, 

 and Ameghino in Argentina, continued to use a continuous 

 notation for the two sets of teeth combined) and the usual habit 

 among zoologists in general was to speak of them individually 

 as " second premolar," " third molar," and so on. Even here, 

 however, an important difference cropped up owing to Hensel 



* I may explain that in my own descriptions the palate of any given animal has al 

 ways been measured from the same anterior point, gnathion or henselion, as the skull 

 itself, this latter being indicated by the use of the words basal or basilar. 



