British Fauna and Flora. 59 
this severance took place in comparatively recent times would 
account for the comparatively small number of species which 
are peculiarly British. 
Taking the animal kingdom in detail, Mr. Wallace shewed 
that, in the opinion of the best authorities, our islands have 
no peculiar species of Mammalia or Reptiles, but of birds 
there arethree species, the Red Grouse (L. scoticus) the 
English Coal Titmouse (P. britannicus) and the British Long 
Tailed Titmouse (A. rosea), which do not occur elsewhere. Of 
fishes there are fifteen species, all of freshwater fish, which are 
not to be found on the continent ; six of these are peculiar to 
Ireland, two of them to be found only in one lake. Of the 
British Trout, two species are peculiar to the Orkneys, one 
to the lakes of Dumfries (which are little more than moderate- 
sized fish ponds connected with Dumfries Castle), one to 
Wales, two to the English lakes, and three to the Scotch lakes. 
The difference between these species is not in colour only, but 
in structure, and the favourable conditions under which they have 
probably been developed was explained in detail by Mr. Wallace. 
Passing to invertebrate animals, Mr. Wallace pointed 
out that insects, being smaller in size, and therefore more 
easily overlooked, were more difficult to deal with; but 
there is every reason to believe that there are many species of 
insects which occur only in the British isles. The English 
climate, from its mildness in winter, and other peculiarities, is 
favourable not only to the production of new species, but also 
to the survival of others, which are not able to endure the 
winter of many parts of the continent. Among the Lepidoptera 
there are over one hundred species, which have been found in 
our islands, but which are not known to occur:on the continent. 
After making every allowance there are probably seventy ofthese 
species which are really peculiar to Great Britain and Ireland. 
Of these seventy species there are only unique specimens of 
some, others are very rare, and others rather common. Two 
of the unique specimens were taken at Sanderstead, near 
Croydon, one in 1848 and the other in 1854. Mr. Wallace 
exhibited a case of Butterflies and Moths, lent to him by Mr. 
Charles Stevens, containing, amongst others, the large Copper 
Butterfly (P. hippothoe), formerly abundant in some parts of 
Great Britain, but believed now to be extinct, and pointed out 
in it and described some of the unique specimens to which he 
had referred. He also exhibited a case of Butterflies and 
Moths taken in the Isle of Man, and with them a series of 
the specimens most nearly resembling them which are to be 
found in the other British islands, and the peculiarities of each 
were pointed out and described. Of Coleoptera about seventy- 
two species, and of Trichoptera three species are peculiar to 
