206 B. NATURAL HISTORY. 
Fig. 4. 
Fig. 5. 
Prf 
S. AgM ss-enereresn—---- 
Pier a 
ID) oes 
Figs. 4 and 5. — Lystrosaurus frontosus (from Cape Colony) ; profiles. (Fig. 
5, diagram with arches removed.) Lettering as in figs. 1 and 2, with the follow- 
ing additions :— 
Etvom. . Ethmovomerine. Col. 
Sph.... Sphenoid. 
Pro. ... Prodtic. 
Pter.. . . Pterygoid. 
ecb Columella. 
Ectp.... Ectopterygoid. 
Subart. . Subarticular. 
