260 The Creodonta. [March 
rial,” is especially well marked in Oxyæna (Fig. 3) and Stypo- 
lophus. 
All stages of diminution of the anterior of the two inner cusps 
of the inferior molars may be seen in the genera of Centetidæ, as 
for instance in Ictops and Diacodon, until a true quadrituberc- 
late molar is reached as in Mioclenus. In Miacis and Didymic 
tis one tubercular-sectorial remains with one or more tubercular 
The process of developing a tubercular inferior molar from a tt 
tubercular tooth, is the reverse of what has taken place in the 
Carnivora, where the tubercular-sectorial has, by loss of pafs 
Mea Ai 
: on Me 
Fie. 3 Oxyena fo rcipata Cope, mandible from the Wasatch bet rooth 2 
baste kal natural size. Original from Report U. S. G. G. Survey 
WwW 
lars 
G. M. osmi, Vol. tv, The numbers a the approximate premo: 
molars ge 
s 
become a true sectorial. With these explanatory cea 
sent the following definition of the families. I have 
used the shape of the astragalus as a family ssn h ed 2 
majority of the Creodonta its trochlear face is not pare 
the Mesonychide it is strongly grooved. In wee 
some species of Stypolophus, as well as in the moles, ! 
grooved : 
I. Inferior DE AA premolariform. Mem” 
Inferior molars consisting of a cone and heel. n... 000er ttt "ene 
Inferior molars with a blade formed of anterior and pedi cuii: 
