202 T)R, r. .T. TOT?RYTn -vr AjoR oy iNnocEXE sqihrrels. [Feb. 28, 



very small details. The only inference I Mish for the present ' to 

 draw from thi> fact and its consequences is, tliat Prof. Fleischmann, 

 too, is on his way to become an opponent of trituberculism. 



It would appear that the Allotheria, the Multituberculata 

 Kur e^oxn^, ought to have been a stumbling-block for the theory. 

 But this is not the case ; they have been simply pushed aside on 

 account of being an aberrant order. Nevertheless, I shall refer to 

 them later on. 



The dentition of Eodentia has as yet not much been dealt with 

 in relation to the tritubercular theory. Scott was the first to 

 touch upon the question, when describing the PIcs!arctoiin(S sciu- 

 roide-'<, S. & O,, from the Uinta formation'-, considered by him to be 

 " one of the oldest, if not the very oldest known form of rodent." 

 Owing to the im])ortance ^\ hich for this reason is attributed to the 

 fossil, I must d\\ (41 upon the subject at some length. Scott has 

 shown to his own satisfaction and to that of others that the 

 superior molars of PUsiarctoinys sciuroides " are plainly of the tritu- 

 bercular pattern," and that " the inferior molars show the anterior 

 ti'iangle of three cusps \\ ith a talon behind, or w hat Cope has termed 

 tlie tuberculo-sectorial molar."' It might be questioned at once 

 whether this specimen, the teeth of which are much A\orn according 

 to the author's own assertion ^ and according to what appears from 

 the diagram ' and the figures ', is a proper object from ^hich to draw 

 such important inferences. I fail to see in its molars anything 

 (dse than the usual Sciuromorphine type, which I agree with 

 Scott in considering as a \ery old one. I have myself pointed 

 this out twenty years ago in some fossils (Scivms sj>ectohU'is) from 

 the Eocene of Egerkingen '', which are rather older than the I'inta 

 formation. The Uinta bed< are considered by Zittel ' to be Lower 

 Oliogoeene, whilst the Bohnerz of Egerkingen has important rela- 

 tions with the oldest Eocene of Europe (Reims) and America 

 (Puerco)\ On the other hand, this type is still in existence, and 

 widely spread among liAing Sciuromorpha. 



I think that Scott is mistaken in what he considers to be the 

 homologies, in the lower molars of PJi'-^iarctoini/s, of the anterior 

 triangle of Ungulates, Creodonts, and Lemuroids. This anterior 

 triangle is formed, as clearly shown by unworn molars of most of 

 the Sciuromorpha, by the autero-external and antero-internal 

 cusp (the jiroioi-oiii'f and mdaconul according to Osboru's no- 



' See also W. B. Scott, " The Evolution of tlie Premolar Tefth iu the Main- 

 mak" (Proc. Ac. Nat. Sci. Philad. 1802. p. 410). 



- William B. Scott and Henry Fairfield Osborn. " The Mammalia of the 

 Uinta Formation" (Trans. Amer. Pliilos. Soc. n. s. vol. x^i. pt. iii. Aug. 20, 

 1889, pp. 470-47^!). 



' L. c. p. 477. 



' P. 476. 



"' PI. xi. 1 r, ] d. 



''' Forsyth Major, " Nageriiberreste aiis Bohnerzen Siiddeutschlands und der 

 Schweiz." 



' ' Ilandbiicli der Palaontolugie, I. Palaozoologie,' IV. Band, 1892, p. (50. 



' L. Eiitimeyer, 'Die Eociine Siiiigethierwelt von Egerkingen," Abhnndl. 

 schweiz. palaont. Ges. xviii. 1891. 



