28 



SIK E. OWEN ON THE UPPER 



4. Note on the E.esemblan'ce of the Uppee Molae Teeth of an 

 Eocene Mammal (NEOPEAGiArLAx, Lemoine) to -those of 

 Teittlodon. By Sir Eichaed Owei^, K.C.B., F.E.S., P.G.S., &c. 

 (Eead ]S"oveinber 19, 1884.) 



Shoetlt after the communication to the Geological Society of the 

 paper on Tritylodon * I was favoured by the author, Prof, Lemoine, 

 with a copy of his ' Memoire,' " Etude sur le Neoplagiaulax de la 

 Eaune Inferieure des Environs de Eeims " t. The chief interest of 

 that ' Memoire ' was, to me, the dental characters of the small 

 mammal there discovered, especially those of the upper molar teeth ; 

 while the general characters of the dentition, by their resemblance 

 to those of the Mesozoic Plagiaidax, are also notably suggestive J. 



With a premolar, in relative size, shape, and sculpturing of crown, 

 so closely repeating the peculiarities of that tooth in our Oolitic 

 marsupial as to have suggested the generic name of the lower 

 Eocene mammal of Eeims (Neoplagiaulax), were associated true 

 molars more nearly resembling, in those of the upper jaw, the 

 corresponding teeth of Tritylodon than did the teeth of the 

 geneisi 2Iicrolestes and Stereognathus with which I compared them §. 



Eigs. 1-3. — Upper Molars of I^eoplagiaulax eocsenus, Lemoine, after 

 Lemoine, Bull. Soc. Geol. Fr. ser. 3, torn. xi. pi. vi. Jigs. 17 Uy 

 17 I, Si^ 17 e. 



Fig. 1. Eig. 2. Eig. 3. 



^^^^ ^^f ^^^ 



a 

 1. From beneath. 2 & 3. From the sides. a. Natural size. 



The figures 11 u, 17 I, 17 e, pi. vi, of M. Lemoine's 'Memoire' 

 appended to the present note, will enable the resemblance of the 

 upper molars of Neoplagiaidax eoccenus to those of Tritylodon to be 

 appreciated. In size the diiference is almost as great as that shown 

 by the molars of Microlestes \\. And here I may observe that, as 

 the lower molars of Neoplagiaulaar have only two longitudinal series 

 of tubercles, it suggests a surmise that the lower molars of Tritylodon 

 may be found to present the same less complex character as com- 



* Quart. Journ. Geol. Soc. Feb. 1884, vol. xl. p. 246, pi. vi. 



t Bulletin de ]a Societe Geologique de France, 3e serie, t. si. p. 249. 



\ Compare " pi. v. figs. 1-3," with figs. 9 and IG, pi- iv. of my " Extinct 

 Marsupials of England," pp. 75-87, in the ' Extinct Mammals of Australia,' 

 4to, 1877, p. 75. 



§ Locfcit pp. 150, 151. 



II Loc. cit. pi. tI. figs. 8-10 (magn. 3 diameters). 



