TJwmas Nomenclature of Measurements. 195 



and his school in Germany numbering the premolars from be 

 hind forwards, while naturalists of other nations counted from 

 before backwards, as with the incisors and molars, a difference 

 often productive of fatal confusion. 



Of late years, however, partly owing to an increasing concensus 

 of opinion that the seven cheek-teeth of Placentals, four pre 

 molars and three molars, are serially and individually homolo 

 gous with the seven of Marsupials, formerly reckoned as three 

 premolars and four molars, many naturalists have again begun 

 to think that a continuous numeration might be the best one. 



But the difficulties in the way of its adoption are very great, 

 largely owing to the absence of any convenient and suitable word 

 in English less clumsy than * ' cheek-tooth , " to express a tooth 

 of the combined premolar and molar series. To speak of the 

 " first cheek-tooth " or of the " predecessor to the fourth cheek 

 tooth ' ' would be so retrogressive a step that I am sure no 

 one would adopt it. But if instead of trying to find a word 

 for the series combined with a numeral to show the position, 

 we were to have a name for each tooth, we should get some 

 thing of the immense convenience we have all realized in having 

 definite names for the canine and the carnassial teeth, the latter 

 name being found of value in spite of the fact that the upper 

 and lower carnassials are not homologous with each other. Such 

 names might be made from the positions of the teeth if their 

 meanings were not so obtrusive as to confuse the minds of per 

 sons who do not readily understand how a tooth should be called 



the second " or " secundus ' ' when it is actually the most an 

 terior of the series. 



Now it fortunately happens that while the Latin terms ' ' pri 

 mus, " " secundus, ' ' etc. , express the serial positions too clearly 

 for the convenience of weak minds, Latinized Greek terms have 

 just about the right amount of unfamiliarity which would enable 

 them to be used as names without their serial origin being too 

 much insisted on. Moreover, their construction is similar to 

 the process we all use in making generic names, and so far as I 

 know they have never been previously utilized in zoology. 



Then, after Latinizing the Greek ordinal terms -Rptoros^ etc. 

 for the cheek-teeth of the upper jaw, the same modification as 

 is already used in cusp nomenclature might be adopted for those 

 of the mandible. 



