Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/584

 " Besides a large number of Wombats (Phascolomys) the existence of very Wombat-like Kangaroos, or rather Wallabies (Halmaturi), is proved by fossil remains of these animals. In fact the whole tribe was different from those of the present day, on account of the shortness of their extremities ; the skull and lower jaw also differed considerably ; and in the catalogue which I am preparing of these remains I have divided the Kangaroos into three distinct groups : —

" 1. Macropus, with dentition as the present Kangaroos, whereof Macropus major is the type. Premolar soon lost.

" 2. Halmaturus, represented by the smaller Kangaroos, known as " Wallabies." Head rather shorter than in the true Kangaroos. Premolar permanent.

" 3. This group comprises all the gigantic species which have been referred to Macropus, but which in reality are gigantic Halmaturi, with very strongly developed premolars, resembling those of the genus Bettongia. But as there are two very distinct kinds of premolars developed, I have subdivided the Halmaturi again : —

" a. Into such as have long, narrow, and compressed premolars, moderately elongate heads, and the rami of the lower jaw but slightly anchylosed ; and

"b. Into the Wombat-like Wallabies, with short heads, strongly anchylosed lower jaws (immovable jaws, in fact), incisors without cutting-edge. (The present Kangaroos and Wallabies have the rami only slightly anchylosed, and use the teeth like scissor-blades for cutting the grass.) The premolar tooth in this group is very compact, rounded, molar-like, and approaches in shape the same tooth in Diprotodon or Nototherium.

Discussion.

Prof. Owen remarked upon the importance of the researches made by Dr. Krefft and Prof. Thomson in the caves of Wellington Valley. No traces of man had been found. The numerous remains of Mammals, especially the Herbivorous species, had doubtless been carried into the caves by Thylacoleo.

Prof. Busk inquired on what grounds Prof. Owen decided that the teeth of Thylacoleo, of which casts were exhibited, were Carnivorous.

Prof. Owen indicated the remarkable compression of the tooth and the absence of the spatulate form proper to the Kangaroos, also its association with a large " carnassial" and small "tubercular" tooth, as characteristic of Thylacoleo and indicative of carnivorous habits.

Mr. W. Boyd Dawkins stated that Thylacoleo was most closely allied to Plagiaulax, which was probably a true Herbivore. He indicated the importance of the question, as, if Thylacoleo were a Carnivore, Plagiaulax would be one also.

Prof. Owen remarked that Plagiaulax was also a Carnivore. The premolars resembled the small tubercular molars of the Hyaenas,