566 FOSSIL MARSUPIAL AVITH LARGE GROOVED PREMOLARS, 



impossible to split the stone without breaking either the bone or 

 the teeth. 



Taking into consideration the various points of structure so far 

 as known, it will be noticed that not only does the form present 

 features which distinguish it from any known genus, but that in 

 it we have a combination of characters which render it difficult 

 to be certain whether it belongs to the Macrojjodidce or to the 

 PlicdangtridfE. As regards the structure of the jaw, the affinities 

 on the whole are with the latter, and as regards the teeth 

 apparently with the former. The absence of any opening between 

 the dental canal and the hollow on the outer side of the hinder 

 part of the jaw would seem to remove the form from the Macro- 

 podidce and point to its connection with the Phalangers. But 

 this point cannot be of any great value, as though the opening is 

 generally absent in the Phalangeridce it is present in the genus 

 Petatirus. The large grooved premolars, though much better 

 developed proportionally, appear to be constructed on the same 

 type as those of .Epyprymrtus (Hypsijnymnus) and a type quite 

 distinct from that of the Phalangers. In IVichosurus where there 

 are rudimentary indications of grooves it is on the hinder part of 

 the tooth, the anterior part being developed into a powerful 

 smooth cusp. The molars present a somewhat archaic type. 

 There is no indication of ridging as in most of the existing types, 

 nor is there the simple regularity of cusps found in Petaurus. In 

 the little accessory tubercles we seem to have a feature suggestive 

 of the multi-tubercular molars of the Secondary Marsupials. The 

 minute premolars certainly recall the similar rudimentary teeth 

 in Pseudochirus^ Petaurus, ikc, but similar rudimentary teeth 

 must also have been present in the primitive Macropodidce. 



On the whole it would seem that we have in Burramys one 

 more link in the chain binding the Kangaroos and the Phalangers. 

 The main links would thus be — MacrojJus, jEpyprymnus, Hypsi- 

 j)rymnodo)i, Burramys. 



The types have been placed in the Australian Museum, Sydney. 



