BY H. H. SCOTT AND < uvi: B. LORD. 83 



we call the male of N. mitchelli — in a word, Nototherium 

 mitchellif male and female, are quite distinct from 

 X iilntln n a in tasmanicum, and as a full table of 

 characters will be given, it is only needful here 

 to investigate the question of the presence and 

 1' a parietal crest. De Vis made much of 

 this, and d s ems a good point to inv especially 



as we can appeal 1" Kangaroos, Wombats, and Native 

 Bears, among existing marsupials, and to the Diprotodons, 

 and the various Nototheria, among extinct forms. Exactly 

 what the ancestor of the common gn up may have shown 

 in the connection we cannot, of <■ jay, but for a 



working hypothesis, let us assume a mor or less rounded 

 parietal region, with an interparietal bene that formed 

 lion of the calvarium, and divided the parietala upon 

 the median— sagittal mture. 



How, it may b ask this lit in with the con 



ditions obtaining in the animals already named' 



1. In the Kangaroo, th cranium is rounded, the in- 



terparietal, in early life, appeals upon the sur- 

 face, separat s the parietals, and throws a dart 

 forward into th a tal suture. Two muscular 

 lines bound the suture, starting ;b closely to- 

 ll r a- 2 mni.. and opening outwards to 8 mm. 

 at th frontal suture. At maturity this becomes 

 a bony strip-like platform, slightly elevated 

 abovi the parietals and front 



2. Tin- Wombat starts life with a rounded cranium, 



a very small interparietal, that early iu-> - with 

 the supra-occipital, two muscular lines (26 mm. 

 apart, at the occiput, and 35 mm., at the frontal 

 suture) outlin the future platform, thai charac- 

 terises the Wombat's skull at maturity. 



3. En the Native Bear, the interparietal early fti 



with the supra-occipital, but continues to carry 

 forward its full complement of bony matter, div- 

 iding the parietals. by its shield-shaped inter- 

 posit i< n, to a distance of 8 mm., for the first 18 

 mm. of their journey forward, upon the root' of the 

 skull. forward to the frontals, the 



parietals develop a sagittal crest (at maturity) 

 and ancestoral bounding lim rly life. 



In all tie.- the platform, or the strongly marked 

 a t he i asi may be, i-- elarx raid in the method 

 shown from tin ordinary ancestoral crania] elements and 

 a platform ne a crest, or a crest a platform, 



as- a sexual modification in the mature animal, whatever 

 slight (han- a may obtain in early life Accordingly, the 



