280 LLOYD'S NATURAL HISTORY. 
ORDER MULTITUBERCULATA. 
As already mentioned, the serial position of that re- 
markable group of extinct Secondary Mammals, generally 
known by the name of Multituberculata, cannot at present be 
definitely determined, although the balance of evidence ts in 
favour of their being more or less intimately related to the 
existing Monotremes. Whether, however, they should be 
included in the same order with the latter, or whether, as is 
more probable, they should constitute an order by themselves, 
is likewise a matter of uncertainty. If they really indicate a 
distinct order, it may prove that the Monotremata and Multi 
tuberculata constitute two ordinal groups in the sub-class 
Prototheria. 
From a superficial resemblance between the teeth of certain 
members of the family and those of the Rat-Kangaroos, it was 
at one time considered that the Multituberculata belonged to 
the Diprotodont Marsupials, but subsequent investigations have 
led to the abandonment of this view. 
The main reasons for placing this group in the ne’ghhbour- 
hood of the Monotremes are, firstly, that while their molar 
teeth are quite unlike those of all other Mammals, they present a 
certain distant resemblance to the deciduous teeth of the Duck- 
bill; and, secondly, that in the one instance where the bones 
of the shoulder-girdle have been discovered, these are of the 
characteristic Monotrematous type; that is to say there is 
a distinct coracoid and metacoroid, and probably, therefore, 
an interclavicle. 
Ranging throughout the whole of the Secondary period, that 
is to say from the Triassic to the Cretaceous rocks inclusive, 
the Multituberculata also survived into the lowest division of 
