Theriodontia — Clep sydrojoidce . 
59 
most reptiles, living and extinct, the teeth that are worn away by Table-case, 
nse, or otherwise lost, are replaced by others that are constantly ^°- 
forming in the jaws; but there is no evidence of preceding teeth, 
like the milk-teeth in mammals, nor of successional teeth, in the a on tia. 
jaws of the Tlieriodonts. From this negative evidence Sir Richard 
Owen assumes them to have been “ Monopliyodont ” i*ep tiles, 
having but one set of teeth, which were permanent, during life. 
He has described eleven genera, varying in the size and form of 
the skull and teeth. The specimens exhibited have all been 
obtained from rocks of Triassic age in South Africa, and are the 
type-specimens of the species figured and described in the work 
already quoted. 
Fig. 80. — i, Palata 1 , and b, Occipital aspect of cranium of Bmpedias molaris (Cope;; 
{ nat. sizp, irom the Permian of Texas, North America. 
Family Clepsydropidas. — These Theriodonts differ from the Naosaurus. 
Galesauridjs either in having teeth on the palate, or by the 
extraordinary character of their dorsal vertebrae, in which large 
intercentra are typically present. These forms a 1 belong to 
