Tlwmas — Nomendatnre of Measurements. 19-5 



niid his scliool in (Icniiany numbering tlic premolars from be- 

 hind l'(ir\v;ir<ls, wliilc natui-alists of Dtlicr nations eounted from 

 before l)aekwards, as with the incisors and molars, a difference 

 often productive of fatal confusion. 



Of late j^ears, 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 l)egun 

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



But the ditiiculties in the wa.y of its adoption are very great, 

 la i-gcly owing to the absence of any convenient and suitable word 

 in Knglish 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 ri'tnjgressive 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 sIumv the position, 

 we were to have a name iV)r each tooth, we should get some- 

 thing of the innnense 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 tlie fact that the upper 

 and lower carnassials are not homologous with each other. Huch 

 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 tlie convenience of weak minds. Latinized Greek terms have 

 just about the right amount of unfamiliarity which would enable 

 them to l)e used as names without tlieir serial origin being too 

 much insisted on. More(jver, their construction is similar to 

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

 know they have never l)een previously utilized in zoology. 



Then, after Latinizing the Greek ordinal terms -/^"jr-zv, etc. 

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

 is already used in cusp nomenclature miglit be adopted for those 

 of the mandible. 



