SECONDARY MARSUPIALS, 273 
other Tertiary Marsupials in either Europe or North America, 
thus justifying the conclusions arrived at above as to a former 
connection between South America and Australia. 
An interesting anecdote in connection with the demonstra- 
tion of the affinities of Didedphys gypsorum of the gypsum 
quarrics of Montmartre, as detailed by Owen, may be appro- 
priately introduced here. The affinities of this fossil were 
originally deduced from the characters of the jaws and teeth ; 
“but these were associated with other parts of the skeleton in 
the same block of stone.” When Cuvier expressed his con- 
victions of the Opossum nature of the fossil from the parts 
first examined, his scientific associates were incredulous. He 
invited them, therefore, to witness a crucial test. On the slab 
containing the jaws and teeth, the outline of the back part of 
the pelvis was also exposed, the fore part being buried in the 
matrix. By his delicate use of the graving-tool, Cuvier 
brought to light that part with the two Marsupial bones in 
‘weir natural position. He thus demonstrated that there had 
been buried in the soft fresh-water deposits, hardened in after 
ages into the building-stone of Paris, an animal whose genus 
at the present day is peculiar to America. 
FAMILY TRICONODONTIDA®, 
. The whole of the remaining families of the Marsupials are 
mainly confined to the Secondary rocks, although a few sur- 
vived into the earliest portion of the Tertiary period. All are 
of small size, and some are extremely minute. 
In the present family the molar teeth, as shown in Fig. 3 of 
the accompanying diagram, consist of three simple compressed 
and cutting cusps arranged in the same longitudinal line; 
the upper teeth biting on the outer side of the lower ones. 
_ In the upper jaw the number of teeth is unknown, but in the 
lower jaw there were three pairs of incisors, one of canines, 
2 t 
