rounding, parietal foramen. An interparietal and small tabulars. Premaxillae fused and always toothless, and in life covered with horny beak. Maxilla usually with an enlarged, permanently growing canine, which, however, is absent in the females of some genera, and generally with a number of small molars often irregularly arranged in more than one series. Molars are always present on the mandible if in the maxilla, but there is never any canine present. Prevomers fused. A rudimentary false palate, no teeth on palatal bones. Stapes large. Occipital condyle tripartite. Dentary, angular, and surangular large; no coronoid. A mandibular foramen. Sclerotic plates in orbits. Vertebrae amphicoelous; no intercentra back of atlas; four to seven sacrals. No parasternals. Legs short and stout, hands and feet short; an entepicondylar foramen. Phalangeal formula 2, 3, 3, 3, 3. A thyroid foramen in pelvis; ilium projecting in front of acetabulum. An ossified sternum. The shoulder girdle has the coracoid and precoracoid well developed, and a distinct but short acromion. There is a small cleithrum known in Dicynodon and Cistecephalus, and possibly present in most other genera.
Family Dicynodontidae. Middle Permian. Dicynodon Owen, Pristerodon Huxley, South Africa.
Upper Permian. Tropidostoma Seeley, Diaelurodon Broom, Prodicynodon Broom, Eocyclops Broom, Emydops Broom, Diictodon Broom, Emydorhynchus Broom, Emyduranus Broom, Taognathus Broom, Cryptocynodon Seeley, Endothiodon Owen, Cistecephalus Owen, Chelyrhynchus Haughton, South Africa, Dicynodon Owen, South Africa and Russia.
Lower and Middle Triassic. Dicynodon Owen, Lystrosaurus Cope, Prolystrosaurus Haughton, Myosaurus Haughton, South Africa.
Upper Triassic. Kannemeyeria Seeley, Gordonia Newton, Geikia Newton, Scotland. Placerias Lucas, Brachybrachium Williston, Wyoming.
D. Suborder Theriodonta
Carnivorous Therapsida with more or less differentiated dentition, including at least one pair of upper caniniform teeth; a prominent coronoid. Vertebrae never notochordal; few or no teeth on palate bones. No cleithrum. Manus and pes, so far as known, rarely primitive.
