PRE ENT D A Ee d a eani i aa ON ie re aes Pr 
Other a] 
1884. | The Tertiary Marsupialia. 693 
sky,too soon lost to science, spent much time in the south of France 
among the formations which most nearly represent the American 
Laramie formation, but found no Mammalia. It remained for 
Mr. Wortman to crown a 
series of successful expedi- 
tions by the discovery of the 
Meniscoéssus conquistus in the 
Laramie formation of Da- 
kota, its loose teeth being 
found mixed with the teeth 
of dinosaurs and scales of 
gar-fishes. The characters of 
the molar teeth are highly 
appropriate to the geological 
age of the genus, the supe- 
rior molar resemblinhg bot 
that of the Jurassic Stereog- 
tathus and the Eocene Poly- „Fie: 7.—Fig. adtad serratus Man 
mastodon. Stercognathus obliticus, 2, from Owen. Fig c, 
right fourth upper molar of 77itylodon longe, 
à third premolar, In the living genera the fourth premolar 
resembles a true molar. It is necessary to remember this fact in 
Me attempt to ascertain the phylogeny of the Multituberculata. 
_ 'S not an entirely easy task, owing to the questions which 
‘rise as to the origin of the cutting premolars themselves. In 
s‘neral it is true of Mammalia that simple premolars precede the 
vmplex in time; but an exception to this rule is to be seen in the 
ig Superior sectorial tooth of some Creodonta and Car- 
Whether the premolars of this family are primitive or 
vative is not as yet known. If they be primitive they may 
a... Modifications of the serrate teeth of the herbivorous 
uria or Theromorpha. The complex character of the pre- 
in the older Tritylodon suggests the possibility of the 
ternative. The general history of the Plagiaulacide con- 
‘This 
? tooth ma possi k 
Neturatisr, ma. a ag to a Saurian. 
