INTRODUCTION. X1x 
distinct species, having found their way to our coasts, one 
of them probably from the Mediterranean, and the other 
from the American shores across the Atlantic. The former 
is the Coriaceous Turtle, Spargis Coriacea, called by 
Merrem by the specific name of Mercurialis, on account of 
its having been in ancient times dedicated to Mercury, by 
whom its shell was believed to have been employed in the 
construction of the lyre. Of this species two specimens 
are recorded by Borlase in his History of Cornwall, as 
having been caught in the mackerel nets off that coast in 
July 1756, the detail of which is given in the description 
of the species. 
I have been induced to enter thus at large into the his- 
tory of this tribe of reptiles, because, although we do not 
possess any British species, there is every reason to believe 
that several of the fresh-water species, both of Europe and 
North America, might be naturalized in the southern parts 
of England. The Terrapene Europea, the common lacus- 
trine Tortoise of the Continent, is found in Portugal, Spain, 
Italy, and Greece, in France, and even in Prussia. These 
Tortoises are eaten by the inhabitants of all the countries 
in which they are found ; and as they live principally upon 
small fish, the air-bags of which they reject, it is said that 
the people are wont to judge of the quantity of Tortoises to 
be found in a lake or pond, by the number of air-bags 
which are seen swimming on the surface of the water. I 
once placed in a small pond, in which were some of these 
fresh-water Tortoises, six small living fish; and on the 
following morning I found the air-bags of five of them 
floating on the surface of the water, and the sixth fish still 
alive. In some parts they are fed upon grains, and on 
other nourishing food, and fattened for the table. There 
are also several American species of mys, or fresh-water 
