176 Transactions of the South African Philosophical Society. 
longer required as supports for the palatal roof, become much 
reduced, and are retained only as supports for the cartilage of 
Jacobson’s Organ. 
The stages by which the Theriodont secondary palate has been 
formed from a simple palate of the Dimetrodon type are apparently 
analogous to the steps by which the Crocodilian palate has been 
evolved from the simple palate of its Phytosaurus-like ancestor. 
The Anomodont palate is probably a specialised modification of 
the primitive Theriodont type, where the Theriodont character is 
somewhat obscured by the great development of the premaxillary. 
Whether the prevomer is lost or anchylosed with the premaxillary 
present evidence does not show. Theoretically it seems not im- 
probable that the prevomer is retained anchylosed with the 
premaxillary, and the condition in Endothiodon would seem to 
confirm this view. The direct evidence, however, is rather against 
this view, and it is quite likely that the prevomer is lost, as frequently 
happens in mammals, e.g., Pteropus, Echidna, &c. 
I can find no trace of a transpalatine element in any Anomodont 
skull, nor of an “ infranasal’’ bone. 
JEAbpe sh, WOR, 
AA, BB, CC, approximate planes of Huxley’s sections of the snout of Ptycho- 
siagum; Ju, Jugal; Mx, Maxillary; Pa, Palatine; Pmx, Premaxillary ; 
P.S., Presphenoid; Pt, Pterygoid; P.Vo., Prevomer; Vo, Vomer. 
Fic. 1. Palate of Ptychosiagum. 
. Median section of snout of Ptychosiagwm. 
3. Section across Premaxillary in region of median ridge of Oudenodon. 
,, 4. Section near posterior part of Vomer in Owdenodon. 
5. Palate of EHndothiodon (Hsoterodon) wniseries—partly restored. 
(Reduced. ; 
bo 
99 
