4 
Insectivora.— Mammalia with small cerebral hemispheres which 
do not cover the olfactory lobes, nor the cerebellum; with numer- 
ous clawed digits, and a third trochanter of the femur; with a 
transverse glenoid cavity for the mandible. 
Superior incisors normal, not growing from persistent pulps; 
canines large; premolars compressed. Astragalus not grooved 
above, articulating with the cuboid as well as the navicular ; five 
toes on the hind foot ; Creodonta. : 
Superior incisors large, growing from persistent pulps, and 
without enamel on the sides ; superior canines small when present ; 
premolars wide or tubercular ; Tillodonta. 
These suborders of the order Insectivora do not differ among 
themselves more than do those of the Marsupialia, and constitute 
a series of parallels with them. Thus the Creodonta resemble the 
Sarcophaga, the Insectivora vera the Entomophaga, and the Tillo- 
donta the Rhizophaga, typified by Phascolomys. 
The genera of the Creodonta differ as follows :— 
I. First and third inferior true molars without internal cusp. 
Last superior molar longitudinal ; last inferior molar carnassial ; 
Ambloctonus. 
II. Inferior carnassials with interior tubercle; no tubercular 
molar; last superior molar transverse. 
Three tubercular carnassials ;? Stypolophus. 
Two tubercular carnassials ; Oxyena. 
III. Inferior carnassial with interior tubercle; a’ tubercular 
molar. 
One tubercular carnassial ; Didymictis. 
The number of toes on the hind foot cannot be certainly stated 
in all the genera, but in Stypolophus hians and another species 
there were probably five, the inner being of reduced size. There 
is present in those species an ento-cuneiform bone which resem- 
bles that of Canis; it is compressed, with one truncate concave 
terminal facet, and an internal oblique one at the opposite and 
proximal extremity. The form of the truncate articular face of 
the distal end indicates the existence of an inner metatarsal bone 
of moderate proportions, which probably supported a small hallux. 
This thumb could not be opposable as in the opossum. 
In general appearance the Creodonta differed from the Carnivora, 
in many of the species at least, in the small relative size of the 
limbs as compared with that of the head, and in some instances, 
as compared with the size of the hind feet. The feet were probably 
plantigrade, and the posterior ones capable of some degree of 
rotation. The probable large size of the rectus femoris muscle 
indicates unusual power of extension of the hind limb. They were 
furnished with a long and large tail. Probably some of the species 
resembled in proportions the Mythomys and Solenodon, now exist- 
ingin Africa and the West Indies, but they mostly attained a much 
larger size. Published December 22, 1875. 
! For i meaning of these expressions, see Syst. Cat. Eoc., New Mexico, 
1875, p. 6 
