136 ArSTBALIAN NATURAL IIISTOEY. 



phalangers have been persistently described as allied to tbe 

 kangaroos — the peculiar short tarsal bones of harmless kangaroos 

 have been explained to be those of great flesh-eaters. New species 

 have been created for the numerous still living bettongs, wallabies, 

 and rat kangaroos, phalangers, dasyures, and thylacines when 

 found fossil ; whilst the peculiar character of the old short-footed 

 kangaroos, with their firmly joined lower mandible, their immov- 

 able incisors, and their other marked distinctions, have never 

 engaged the attention of foreign investigators. So little are our 

 living animals understood that anatomists have not yet pointed 

 out the peculiar structure of the kangaroo's molar teeth. I 

 allude especially to their fangs or roots. I doubt very much 

 that many men have made the observation that, as far as 

 the grinders are concerned, the bandicoots, but more particularly 

 the rabbit-rat or peragalea, are near relations of the wombats. 

 Three years ago such teeth were lithographed for our Museum 

 catalogue, but they have not been published. It must have 

 struck observant people that, with the exception of the Mono- 

 tremes (the platypus and ant-eaters) and the dasyures, all our 

 animals have their hind feet constructed on a peculiar and uniform 

 plan, possessing invariably two small conjoined inner toes, much 

 less in size than the rest of the digits. All, with one exception 

 — the Thylacine — have two bones articulated to the lower part of 

 the pelvis. All marsupials, except the native bear and the dacty- 

 lopsila, have the angle of the lower jaw bent inwards, and all 

 members of the kangaroo tribe have a wide oj)ening at the base 

 of the lower jaw, below the ascending ramus. In all phalangers, 

 bandicoots, and dasyures, this opening is closed, except in the 

 highly herbivorous native bear and wombat, which sometimes have 

 a small foramen remaining. Such a perforation is also present in 

 the very typical Australian form, the Thylacoleo. 



The Teetu. 



{Ornithodelphia or Monoiremata?) 



The Monotremata, who must be regarded as the most ancient 

 mammals known, possess either horny teeth, such as the Orni- 

 thorhynchus, or none at all, lilte the Echidna. The development 

 of these animals appears to have taken place from the Sauropsida 

 (a combination of the two classes of birds and reptiles), and 

 points in the direction of that curious lizard-bird, the ArcJioeop- 

 teryx. This creature, with its toothed beak, is perhaps the most 

 important missing link ever discovered, and when Australia is 

 better explored we shall perhaps find fossil remains of mammals 

 more reptile or bird like than the Platypus or the Echidna. The 

 Australian antiquated living representatives of the early mamma- 

 lian type must have been developed at a period more remote than 

 the Oolite, which preserved the supposed marsupial remains of 



