464 Notices of Memoirs — Prof. Oicen on Nototherium. 



lithologically, but more certainly and effectually by their fossils, 

 "wbich our paper shows only need a little extra perseverance to be 

 detected almost everywhere. It may be urged that if we draw the 

 lines of separation at the horizons mentioned, these boundaries will 

 have as strange an appearance on the map as a diagram of the con- 

 tortions to which their irregularaties are due. But for the purpose 

 of science, the strata must be separated, if not in the present, then 

 in the future, and wherever the divisional lines may be drawn, the 

 same difficulties will occur. 



One thing is plain from the large list of fossils we have dis- 

 covered — all that is necessary is careful untiring work amongst 

 these strange old strata, and these will in time fall into their proper 

 groups, and form as grand and interesting a series as the typical 

 Silurians themselves. 



n^OTioiES oip nvcEiv/noiiR-s. 



I. — On the Fossil Mammals of Australia. — Part V. Genus 

 Nototherium, Owen,^ 



By Prof. E. Owen, F.E.S. 



THE genus of large extinct Marsupial herbivores which forms the 

 subject of the present paper was founded on specimens trans- 

 mitted (in 1842) to the author by the Surveyor- Greneral of Australia, 

 Sir Thomas Mitchell, C.B. They consisted of mutilated fossil mandi- 

 bles and teeth. Subsequent specimens confirmed the distinction of 

 Nototherium from Diprotodon, and more especially exemplified a 

 singular and extreme modification of the cranium of the former 

 genus. A detailed description is given of this part from specimens 

 of portions of the skull in the British Museum, and from a cast and 

 photographs of the entire cranium in the Australian Museum at 

 Sydney, New South Wales. The descriptions of the mandible, and 

 of the dentition in both upper and lower jaws, are taken from actual 

 specimens in the British Museum, in the Museum of Natural History 

 at Worcester, and in the Museum at Adelaide, S. Australia, all of 

 which have been confided to the author for this purpose. The re- 

 sults of comparisons of these fossils of Nototherium with the answer- 

 able parts in Diprotodon, Macropus, Phascolarctos, and Fhascolomys 

 are detailed. 



Characters of three species, Nototherium Mitchelli, N. inerme, and 

 N. VictoricB, are defined chiefly from modifications of the mandible 

 and mandibular molars. A table of the localities where fossils of 

 Nototherium have been found, with the dates of discovery and names 

 of the finders or donors, is appended. The paper is illustrated by 

 subjects for nine quarto plates. 



1 Abstracted from the Proceedings of the Eoyal Society, No. 129, 1871. 



