228 
N ATUIt At. HISTORY. 
When it has buried its body in a stone, it there continues 
for life at its ease ; the sea-water that enters at the little 
aperture supplying it with luxurious plenty. When the ani- 
mal has taken too great a quantity of water, it is seen to 
spurt it out of its hole with some violence. Upon this 
seemingly thin diet it quickly grows larger, and soon finds 
itself under a necessity of enlarging its habitation and its 
shell. The motion of the Pholas is slow beyond concep- 
tion ; its progress keeps pace with the growth of its body; 
and in proportion as it becomes larger, it makes its way far- 
ther into the rock. When it has got a certain way in, it 
then turns from its former direction, and hollows downward ; 
till at last, when its habitation is completed, the whole 
apartment resembles the bowl of a tobacco pipe; the hole 
in the shank being that by which the animal entered. 
But they are not supplied only with their rocky habita- 
tion ; they have also a shell to protect them ; this shell 
grows upon them in the body of the rock, and seems a very 
unnecessary addition to that defence, which they have pro- 
cured themselves by art. These shells take different forms, 
and are often composed of different number of valves ; 
sometimes six ; sometimes but three; sometimes the shell 
resembles a tube with holes at either end, one for the 
mouth, and the other for voiding the excrements. 
This animal is found in greatest numbers at Ancona, in 
Italy ; it is found along the shores of Normandy and Poic- 
tiers, in France : it is found also upon some of the ccfasts 
of Scotland ; and, in general, is considered a very great 
delicacy at the tables of the luxurious. 
CHAP. XXXIII. 
Of Reptiles — The Frog — The Toad — Varieties — Suri- 
nam Toad — O/Lizards — The Crocodile and Alligator 
— The open-bellied Crocodile — The Salamander — The 
Cordyle , fyc. — 27/e Iguana — The Chameleon — The Dra- 
gon — The Siren — The Tarantula — The Chalcidian 
Lizard. 
If we emerge from the deep, the first and most obvious 
class of amphibious animals that occur upon land areFrogs 
and Toads. 
To describe the form of animals, so well known, would be 
superfluous; to mark those differences that distinguish them 
