672 



Dli. II. UIIOOM ON THE STllUCTURE OF TUlO SICULL 



bone is covered as by a skin with n tliin layer of calcareous matrix. 

 Though this obscures tlie niai-gins of the orbits and temporal 

 fossie, all of Avhich are iilletl with matrix, it does not in any way 

 hide the real structure of the skull. 



When seen from above, the most striking peculiarities of the 

 skull are the great posterior width, due to a remarkable develop- 

 ment of what are apparently the sqxiamosals, and the presence 

 of five bony bosses — one above the nose, one over each orbit, and 

 one in each post-temporal region. 



The snout is relatively narrow. The front pait is unfortunately 

 missing, but from what is preserved it must have been sharp, as 

 shown in the figure of the side view, and very possibly it had a 

 horny covering as in Dicynodon. There is evidence of one small 



Text-figure 10. 



Uppor view of the skull of JBurnetia mirabilis, geii. ot sp. iiov. 

 A little less than ^ luit. size. 



incisor, a little in front of the canine, but I do not think there 

 could have been any in front. • The canine is a large, flattened 

 tooth which passes well forward. Behind the canine are four 

 small molars. The canine measures 12 mm. x r)"5 mm. The 

 four molars occupy 18*5 mm., and the iir.st is situated 4 mm. 

 behind the canine. 



The orbits are .small, and wide apart and entirely lateral. 

 Above each is a large oval boss which completely hides the orbit 

 from upper view. A deep traiisvex-se valley is present between 

 the back of the nasal boss and the fronts of the two orbital bosses. 

 There is a fairly wide space between the orbital bosses which is 

 transversely concave and antero-posteriorly slightly convex. 



