62 
HISTORY OF MAURITIUS. 
their volute always turns to the same side? it may be answered, by the same law 
which makes the earth turn from the west to the east. In that case, the sun may 
be the efficient cause, as it is of their colours, which increase in beauty as we 
approach nearer to the line.. 
The Scorpion, which has very long claws, increases its shell every year. Its old 
claws become useless, and it forms new ones. It may be asked, what it has done 
with the old ones? In the same manner the Porcelaine has a thick mouth, which is 
formed in such a way, that it cannot augment its revolutions on itself, if it does not 
succeed in destroying the obstacles to its opening. It is not improbable, that these 
animals possess a liquor capable of dissolving the walls of the roof, which they wish 
to enlarge, and if this dissolvent exists, it might be employed for the stone in the 
bladder, and to destroy those glutinous humours, which resemble the prima materia 
of shells. 
Among the Bivalves , are the common Oyster which adheres to the rocks, and is 
of so rude a shape, that it is necessary to employ an hammer to open it: it is good 
to eat; a kind which is called the leaf, on account of its form; a gray oyster which 
sticks to the sides of ships, and whose shell is beautiful and elastic: this is very 
rare. The pearl oyster is white, flat, thick, and very large; it is found at a great 
distance from land, and is the same as that in which pearls are found; another pearly 
oyster which is still flatter, and of a deep violet colour; it attaches itself by means 
of threads, like the muscle. It is very common at the south-east port, and is found 
at the mouths of the rivers. Its pearls are of a violet colour. 
The oyster called la Tuill.ee , is by no means uncommon; it is of the same kind 
as those, which serve as holy-water pots in the church of Saint Sulpice. It is per¬ 
haps the largest shell fish of the sea. There are to be seen of them, at the Maldivian 
Islands, which require the strength of two oxen to drag them along. It is a very 
curious circumstance, that this oyster is found in a state of petrifaction on the coast 
of Normandy. 
There is also a kind of oyster which is very small, and of a grey colour, that 
resembles, in shape, a Polish saddle; the thorny oyster, which is found in the beds 
of coral, and the Pelure d’oignon , or onion peel, of which we have seen only 
some detached shells. 
There are three kinds of muscle, which are neither curious nor common: they 
resemble, in shape,' the dail of the Mediterranean, and are found among the 
