FOSSIL VERTEBRATES — REPTILIA 629 
Seeley has described the forearm and forefeet of an animal 
that he called 7heriodesmus which may belong to 7yritylodon. 
From the upper Triassic of Wurtemberg, near Hohenheim, 
Fraas has described a single tooth that bears a very striking 
resemblance to the molar teeth of 77itylodon. This tooth he calls 
Triglyphus. 
Diademodon is from the eastern part of the Cape region of 
South Africa; it is known from an imperfect skull showing the 
palate and the teeth. The characteristic part of the skeleton is 
the broadly tubercular teeth; they are flat or cupped on the 
grinding face, with the edges showing many small tubercles ; 
the appearance is not unlike that of the pig or the human tooth. 
In other characters than the teeth the genus is very similar 
to the Cynodontia, and the chief point of interest to us is the evi- 
dence of a gradual progression towards a more and more com- 
plicated style of tuberculate molars that is to culminate in the 
multituberculate type of the most primitive mammals. 
Trivachodon.— Of this genus Seeley says: ‘‘ The skull in this 
genus has a most remarkable mammalian aspect, in form and 
proportion of every part. It was four inches long, as_pre- 
served, and about two inches wide behind. The orbits are cir- 
cular, placed slightly in advance of the middle length of the 
head. The snout appears to terminate conically, rounded above 
and tapering forward, with a rounded alveolar margin. ... . 
Each molar crown has three transverse, conspicuous ridges, but 
the middle ridge is the most elevated, and rises as a distinct 
cusp on the external and on the internal margins.”’ 
Microgomphodon.—This genus is known from the portion of 
a skeleton preserved in a slab of rock from the same region as 
the preceding genera. The teeth are the most’ characteristic 
portion; they are much enlarged in the transverse direction, 
being nearly or quite as longas wide. The surface is slightly con- 
vex from before backwards, and is covered with small tubercles, 
that become much larger at the external and the internal edges. 
The form is a small one, the largest teeth having a transverse 
diameter of two-tenths of an inch only and an antero-posterior 
