﻿DROMATHERIUM. 277 



of Dorsetshire, which is selected from among several allied 

 genera on account of the number of lower teeth being fully 

 known. In this genus there were four pairs of incisor, one of 

 canine, four of premolar, and either seven or eight of molar 

 teeth. The latter differ from those of the preceding genem, 

 and thereby resemble the corresponding lower teeth of the 

 existing Opossums and Bandicoots, in that they consist of an 

 anterior portion carrying three cusps arranged in a triangle, 

 and of a posterior moiety, or heel. It has only quite recently 

 been ascertained that the earliest known of all the Secondary 

 Marsupials, namely, the Amphitherium of Stonesfield, which was 

 described by the French naturalist De Blainville as far back 

 as the year 1838, had teeth of this type. 



The great interest attaching to Aviphilestes^ Af?iblofherium, 

 Amphifherium, and their allies, is that they, and they alone 

 among Mammals, had molar teeth comparable in form, and 

 to a certain extent in structure, with those of the existing 

 Banded Ant-eater (^Myrmecobms) of Australia, which, as already 

 mentioned, may be regarded as the sole and specially modified 

 descendant of these ancient forms of Mammalian life. 



Several genera allied to Amblotherium are represented in the 

 upper Ji-ir^'issic rocks of North America ; amongst them one 

 which has received the name of Dryolestes may be specially 

 mentioned ; and it appears that in that continent certain 

 members of the families survived till the succeeding Creta- 

 ceous epoch. 



FAMILY DROMATHERIID^.. 



GENUS DROMATHERIUM. 



Droinaiherhun^ Emmons, American Geology, pt. vi., p. 93, 

 T857. 

 The earlier;', and at the same time the most i^eneralised 



