REPTILIA. 
29 
from the Karoo Formation of Cape Colony. The dog-shaped 
head of this animal ia enormous compared with the size of 
the backbone, which is stiffened by wide overlapping ribs 
just in front of the hip region. There are two occipital 
condyles at the back of the skull for union with the back¬ 
bone, as in the Amphibia and Mammalia. Most of the 
limb-bones of the fossil have been lost. Cynognathus , 
Lycosciurus , JElurosaurus (Fig. 24), and certain other genera 
(Table-case 31) were doubtless carnivorous ; but Tritylodon 
Fig. 25.—Skull of Tritylodon longcevus, palatal view (a) and upper view (6), 
incomplete behind, from the Triassic Karoo Formation of Basutoland; 
two-thirds nat. size. (Table-case 32.) 
(Fig. 25) and its allies (Table-case 32) have grinding teeth as 
if for a vegetable diet. The remarkably mammalian fore¬ 
limb named Theriodesmus phylarchus (Table-case 32) belongs 
to one of the Theriodonts. 
Sub-order 2.—Dieynodontia. 
The Dicynodonts (“ double-dog-toothed ”) have a beak like 
that of a turtle, but most of them are also provided with a pair 
of tusks, growing throughout life, at the side of the upper jaw. 
Their occipital condyle is trefoil-shaped, as in the Chelonia. 
Dicynodon (Fig. 26) occurs in the Karoo Formation of South 
Africa, and is represented by fine skulls and other remains 
Table-cases 
31, 32. 
Case B. 
Wall-cases 
9, 10. 
Table-case 
33. 
