CONTENTS 



LIST OF ILLUSTRATIONS xi 



I. INTRODUCTION ^ 



II. MORPHOLOGY AND TAXONOMY 6 



A. MAMMALS OF THE MORRISON FORMATION, UPPER JU- 

 RASSIC 7 

 MULTITUBERCULATA Cope 7 



Plagiaulacoidea Simpson 1925 ^3 



Plagiaulacidae Gill 1872 ^4 



CUnacodofi Marsh iSyg '5 



Cte?iacodon serratus Marsh. 1879 16 



Ctenacodon scindens Simpson 1928 20 



Ctenacodon laticefs ( M arsh 1 88 1 ) 21 



Psalodon Simpson 1926 25 



Psalodon foteus (Marsh 1887) 26 



Psalodon fords (Marsh 1887) 26 



? Psalodon mars hi, new species 27 



TRICONODONTAOsborn 29 



Triconodontidae Marsh 1887 3' 



Amphilestinae Osborn 1888 3^ 



Phascolodon Sim^pson 1^2$ 3i 



Phascolodon gidleyi Simpson 1925 3^ 



Afloconodon Simpson \g2$ 32 



Afloconodon como'ensis Simpson 1925 32 



Triconodontinae Osborn 1907 32 



Trioracodon Simpson 1928 33 



Trioracodon bisulcus (Marsh 1880) 34 



Priacodon Marsh 1887 34 

 Priacodon ferox (Marsh 1880) 35 



Priacodon robustus (Marsh 1879) 36 



Priacodon lulli Simpson ig2S 36 



Priacodon grandaevus Simpsor\ 1925 37 



SYMMETRODONTA Simpson 37 



Spalacotheriidae Marsh 1887 38 



Tinodon Marsh 1879 3 8 



Tinodon bellus Marsh 1879 39 



Tinodon lefidus Marsh 1879 39 



5?;)79 



