D1CYX0D0NTIA. 



257 



having a rounded profile and less strongly ridged maxillaries 

 than in the succeeding genus. 



Sp. Dicynodon lacerticeps, Ow. — This species is represented 

 by a skull six inches in length, in the British Museum, of 

 which a reduced figure is given in cut 95, where c shews the 

 canine tusks. 



Sp. Dicynodon testudiceps, Ow. — In this species the skull, 

 and the facial part more particularly, is shorter than in D. 

 lacerticeps. 



Sp. Dicynodon strigiceps, Ow. — The shortening of the jaws 

 and blunting of the 

 muzzle are carried 

 to an extreme in this 

 species, in which the 

 nostrils are situated 

 almost beneath the 

 orbits. 



Sp. Dicynodon 

 tigriceps* Ow.— In 

 this species the 

 length of the skull is 20 inches, its breadth across the 

 widest part of the zygomatic arches being 1 8 inches. It dif- 

 fers from the D. lacerticeps not only in size, but in the 

 relatively larger capacity of the temporal fossae, and smaller 

 size of the orbits. These cavities in D. lacerticeps occupy the 

 middle third of the skull, but in D. tigriceps are wholly in the 

 anterior half of the skull. The profile of the skull in D. lacer- 

 ticeps begins to slope or curve down from a line parallel with 

 the back part of the orbits, but in D. tigriceps it does not begin 

 to bend down until in advance of the orbits. 



Genus Ptychognathus, Ow t . — Three other species, shewing 

 a remarkable angular contour of the skull, with strongly ridged 

 maxillary and upwardly produced mandibular bones, have 



* Trans. Geol. Soc, 2d series, vol. vii , p. 233. 

 S 



Fig. 95. 

 Skull and tusks of Dicynodon lacerticeps. 



