[ 443 ] 
XY. On the Homologies and Succession of the Teeth in the Dasyuridce, with an Attempt 
to trace the History of the Evolution of Mammalian Teeth in general. 
By Oldfield Thomas, British Museum (Natural History). 
Communicated by Dr. Gunther, F.R.S. 
Received April 4,—Read April 28, 1887. 
[Plates 27, 28.] 
In the year 1867 a paper* was contributed to the Royal Society by Professor Flower, 
“ On the Development and Succession of the Teeth in the Marsupialia,” a paper which 
became at once the standard authority on the subject, and in which it was shown 
conclusively that among the Marsupialia only one single tooth ever had a deciduous 
or “ milk ” predecessor, and that this tooth was one homologous throughout the order, 
and corresponding to the last premolar of the ordinary Placental Mammals. 
This paper was followed by another,t in which fresh observations were recorded on 
the presence or absence of a tooth-change in the Marsupials and other Mammals, and 
notes made on the methods of tooth-notation in use—a subject which naturally arises 
out of all investigations into the homologies of teeth. 
Finally, in the article “Mammalia” in the new edition of the ‘Encyclopaedia 
Britannica,’j the same author has given a summary of our present knowledge on the 
subject, to which I am indebted for much information and assistance. 
In the course of preparing a systematic catalogue of the Marsupials in the Natural 
History Museum, my progress was soon arrested by the necessity of understanding 
and applying the very complicated homologies of the teeth, many points on which 
being by no means finally settled by Professor Flower, and the other publications on 
the subject being of a very vague and conflicting nature. The group wherein the 
greatest difficulty occurred was the Dasyuridse, of which only one genus, Thylacinus , 
appears to have had its dental change properly described, and among whose members 
I have noticed several points that I believe to be worthy of publication, and from 
* ‘Phil. Trans.,’ 1867, p. 631. 
t “ Remarks on the Homologies and Notation of the Teeth of the Mammalia,” ‘ Journ. Anat. Physiol.,’ 
vol. 3, 1869, p. 262. 
X Ninth edition, vol. 15, 1883, p. 349. 
3 L 2 
18.10.87 
