7()4 Dlt. K. HnoOM ON" TRITVl.ODOX [M.MV .'*, 



means proven tliat they are at all elosely allieil to the I )i])r<)tcHl()nt 

 Marsupials. There is a little aiiil)i;4:uity in his lan^uaire where 

 he s|»eaks of " nniltituberciilate Entherian inanniials " forininji: an 

 Infraorder of the Marsupialia. Presuin;ibly he means '• iMeta- 

 therian." But it is nranifest he reirards the Multitubereulata as 

 forming a division of the Marsupialia. 



Let us consider in some detail the points that are uiged in 

 favour of this conclusion. 



" Every character," it is said, " is marsupial, as shown in the 

 i^eneral arrangement and function of the teeth and the develop- 

 ment of the skull and skeleton." If by arrangement is meant 

 the occurrence of incisors, premolars, and molars, without canines, 

 the character is not more nuirsupial than rodent, and a somewhat 

 similar arrangement is found in the other Euthei-ian orders. But 

 further the number uf the molars seems to me opposed to any 

 close association of the Multitul)erculates with the Marsu})ials. 

 No living marsupial has more than three premolars and almost 

 every one has four molars. The Multituberculates have apparently 

 as the normal series four premolars and three molars as in the 

 Eutheria. The whole seven are seen in Allodon, and when the 

 nuniber is reduced to six as in Ptilodus there seems little doubt 

 that the loss is in front and not behind. From the position of 

 the lower teeth 1 should incHuc to the viewthat the large grooved 

 tot)tli ill l'tiJoda.ti and the posterior of the grooved teeth in I'lmji- 

 au.hi.r :ind ('lenacodon are 1st true molars. But whatever 

 difference of opinion may be held on the interpretation of the 

 teeth, there can be little doid)t that in structure the molars are 

 (piite unlike anything known among Marsupials. 



In the structure of the skull the only points bearing on the 

 affinities seem to be the following: — 1. ''The malar extends 

 'oackward to the glenoid surface, and apparently joins the lacliry- 

 iiial bone anteriorly as in tiic jisiiig Marsu})ials.'' Though the 

 bai;kward extension of the malar is doubtless a mai'suinal character 

 it is not contineil to Marsupials, being found in Procavia, M(e.ri~ 

 therium, and other Eutherians. It is a typical character of the 

 Cvnodout reptiles and was (loubtless present in all early mannuals. 

 The meeting of the malar and lachrymal is another Cvnodout 

 character which we should expect to fiml in any early mannnal. 

 2. '• The occiput extends init slightly beyond the posterior root 

 of the zygoma." This is a Cynodont character which is not met 

 with in iVIarsupials*. Some aj)proach to it is .seen in some early 

 Kuthcrians. 'A. '" I'he nasals are i-elatively large and broad, ex- 

 panding posteriorly." Still another Cvnodout character which 

 is letainod by mo.st Marsupials, but also by some Eutherians, e.g. 

 //i/atrix. 4. "The premaxillaries are short and widely se|)anited 

 from the frontals by the ascen<ling portion of the maxilla." This 

 (rhaiacter is quite common in Eutherians. 5. '' The relatively 

 broad, hiirh arched palate is perforated by two pairs of foramina.' 



* I'ul is liiuiid III Oriil/li'ir/ii/iii-/ii(s. 



