Gregory: notharctvb, an American eocene primate 



197 



as has been done by Cope, Wortman, Schlosser, and the writer, it must readily be admitted that the 

 important question is not whether the marked divergences of the European and American genera are to 

 be symbolized by the subfamily termination "-inae" or by the family ending "-ida^"; the real question 

 is, rather, whether Adapts and Notharctus are structurally more nearly related to each other than either 

 are to Tarsius, to Tetonius, and to Necrolemur. As to this, if we admit the force of the foregoing argu- 

 ments, the skull characters of the last three genera show that they are rather widely removed from the 

 Adapis-Nothardus group (see p. 230). 



RELATIONS OF XOTHAIK TIX.E AND ADAPIX.E WITH LKMURID.E, AND A DISC USSION OF THE 

 PROBABLE ORIGIN OF THE LEMURID^ 



Dentition 



Preliminary Outline of the Divergence in the Dentition 



It has already been noted that even the earliest members of the Notharctina? are at once excluded 

 from direct ancestry to the Adapinse by the possession of certain specializations in the dentition described 

 by Stehlin. The most general comparison of the dentition in the Notharctinse, Adapinse and Lemurinse 

 may be tabulated as follows. 



Upper canines 

 Lower canines 



Lower incisors 

 Posteroexternal cusp on p"* 



Hypoconid and talonid on p^ 



True hypoconc (from cingu- 



lum) on mi mo 

 Mesostyles on m'^ ni- 

 Pseudohypocones 

 Entoconids on nii mo 

 Metacristid on nii m-i 



Protoconules and nieta- 

 conules 



Pi 

 P2 



NOTHARCTIN.E 



Progressi\ ely caniniform 



Erect, spatulate 

 Xery late and feebly devel- 

 oped 

 Not yet developed 



Aljsent 



Progressive 

 Progressive 

 Progressive 

 Barely indicated 



Originally distinct 



Present 



Normal 



AdAPIN/E 



Stout dagger-like 



Short, sub-premolariform 



Erect, shovel-like 

 Always well developed (ex- 

 cept A. sciiircus'f) 

 Well-developed 



Well-developed 



Never developed 

 Never developed 

 Retarded 

 Progressive 



Less distinct 



Present, often small and 



crowded 

 Normal 



Lemurid.e 

 Compressed 



Procumbent, incisiform styli- 

 form 



Procumbent, styliform 

 Present only in 1 genus (My- 



oxirrhu.s) 

 Usually degenerate (present 



in Myoxicchus) 

 Absent (or degenerate) 



Never developed ' 

 Never developed 

 Degenerate 



Often widely displaced |)oste- 

 riorly 



Degenerate or absent 

 Lost 



P>nlarged and subcaiiiiiiform 



These facts are provisionally interpreted by the writer as follows. 



(1) The dentition of the Notharctinse, apart from a few well-marked specializations (pseudohypocones, 

 mesostyles, etc.), represents a more ancient and primitive early Eocene type. 



(2) The dentition of the Adapinse, on the other hand, is on the whole a progressive derivative from 

 the hypothetical common ancestors of the Adapinse and Notharctinse. 



Except in Mcgaladapis insignis Major. 



