Geological magazine . e teeth there is no difficulty inrecognizing the six elements of the sex-tubercular tooth, all of which are indicatedby letters in Fig. 2, with the exception ofthe metaconule, which is the unletteredridge occupying the middle of the tooth,immediately below the m. The fourremaining elements, lettered a. m. p. andpp., have been developed from the basalcingulum surrounding the molar of JSyra-cotherium; and, accordingly, have nothingwhatever to do with the primitive foldingsof the crown. This origin is very im-portant with regard to the tubercle marked^jjp. Thus in Fig. 2 thi
Geological magazine . e teeth there is no difficulty inrecognizing the six elements of the sex-tubercular tooth, all of which are indicatedby letters in Fig. 2, with the exception ofthe metaconule, which is the unletteredridge occupying the middle of the tooth,immediately below the m. The fourremaining elements, lettered a. m. p. andpp., have been developed from the basalcingulum surrounding the molar of JSyra-cotherium; and, accordingly, have nothingwhatever to do with the primitive foldingsof the crown. This origin is very im-portant with regard to the tubercle marked^jjp. Thus in Fig. 2 this is so stronglymarked as to suggest an origin like theother main tubercles; but its commence-ment as a slight swelling of the cingulumis clearly shown in Fig. 1. To theelements respectively marked a. m. andpp., Professor Osborn applies the termsanterior pillar, median pillar, and posteriorpillar; stating that the latter term is takenfrom the writer of this notice, by whom itis said to have been proposed for the teeth. im inre Fig. 2. — Grinding andouter aspects of a left uppermolar of Anchitherium longi-criste. pr. protocone ; ; me. metacone; ; pi. protoconule ;a. anterior ridge ; m. middleridge ; p. posterior ridge ;pp. posterior prominence. Eevieus—Prof. E. F. Oshorn—Molars of Perissocladyla. 319 of the Horses. To this statement we must take the present oppor-tunity of objecting. The term posterior pillar (although it has been
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1864
