9 
Mammals, which appear to be descended from the extinct 
Mammal-like Anomodont Reptiles of the Permian and Trias, 
make their first appearance so far back as the Triassic or early 
part of the Secondary or Mesozoic period ; a few^ minute teeth, 
representing some small species, have been found in the upper 
part of that formation in Germany and England. Later than 
these are the early Jurassic or Middle Mesozoic Mammals, 
found at Stonesfield in Oxfordshire, wdiere several more or less 
incomplete low^er jaw^s have been discovered, such as those 
named Ampliitherium Phascolotlierinm^ figured in the ‘Guide 
to the Fossil Mammals and Birds.’ In Upper Jurassic times 
also a number of small Mammals lived in Britain, as is demon- 
strated by remains found at Sw^anage. Jaws of allied Mammals 
have been found in the Jurassic and Cretaceous strata of North 
America. 
At the commencement of the Tertiary period “ Placental ” 
Mammals w^ere already abundant, many of them resembling 
living types — a fact wFich shows how imperfect is our know^- 
ledge of the intermediate time, during which these creatures 
must have been gradually developed from their Mesozoic 
ancestors. The Eocene, the earliest of the Tertiary periods, has, 
for example, yielded remains of Bats, Insectivora, Carnivora, 
Bodentia, many Ungulata, and Sea-Cow's. 
The Mammals of the Miocene, Pliocene, and Pleistocene 
periods, for wdiich the visitor is referred to the ‘ Guide to the 
Fossil Mammals and Birds,’ have increased in number and 
variety to the present day. In many instances the extinct pre- 
decessors of our small living mammals w^ere gigantic ; but the 
African Elephant, if w^e except certain extinct members of the 
same group, attains as large a size as any extinct terrestrial 
Mammal, and the evidence of fossil remains does not show that 
AVhales have existed in past times larger than those which now 
swim in our seas. 
The subjoined Table shows the manner in which the Mammals 
are classified and arranged in the galleries devoted to their 
exhibition : — 
