B1VALVED SHELL-FISH. 



373 



be gathered. Every diver is sunk by means 

 of a stone, weighing fifty pounds, tied to the 

 rope by which he descends. He places his 

 foot in a kind of stirrup, and laying hold of 

 the rope with his left hand, with his right he 

 stops his nose to keep in his breath, as upon- 

 going down he takes in a very long inspira- 

 tion. They are no sooner come to the bottom, 

 but they give the signal to those who are in 

 the boat to draw up the stone ; which done, 

 they go to work, filling their net as fast as 

 they can ; and then giving another signal, the 

 boats above pull up the net loaded with oysters, 

 and shortly after the diver himself, to take a 

 new inspiration. They dive to the depth of 

 fifteen fathoms, and seldom go deeper. They 

 generally go every morning by break of day 

 to this fatiguing employment, taking the land 

 wind to waft them out to sea, and returning 

 with the sea-breeze at night. The owners of 

 the boats usually hire the divers, and the rest 

 of the boat's crew, as we do our labourers, at 

 so much a day. All the oysters are brought 

 on shore, where they are laid in a great heap, 

 till the pearl fishery is over, which continues 

 during the months of November and Decem- 

 ber. When opportunity serves, they then ex- 

 amine every oyster, and it is accidental whether 

 the capture turns out advantageous. Indeed no 

 human being can wish well to a commerce, 

 which thus chains such a number of fellow- 

 creatures to the bottom, to pluck up a glitter- 

 ing mouldering pebble. 



CHAP. VII. 



OF MULTI VALVE SHELL- FISH. 



MULTIVALVE Shell- Fish may be considered 

 as animals shut up in round boxes. To view 

 their habitations externally, one would be 

 little apt to consider them as the retreats of 

 living creatures; and still less, to suppose that 

 some of them carry their boxes with a toler- 

 able share of swiftness, so as to escape their 

 pursuers. Of these there are principally two 

 kinds ; such as move, and such as are station- 

 ary : the first are usually known in our cabi- 

 nets by the name of Sea-eggs ; the others are 

 as often admired, from the cavities which they 

 scoop out for their habitation in the hardest 

 marble. The first are called by naturalists, 

 Echini, or Urchins; 1 the latter are called 



l The sea-urchins are very improperly placed in the 

 multivalve division of shells, as they are very different 

 from testaceous worms, not only in their functions, but 

 also in the composition of their shells. They are placed 

 by naturalists in the crustaceous order, the shells or 

 crusts of Echini being composed of phosphate of lime with 

 animal matter ; those- of the testaceous shells being car- 

 bonate of lime. 



Pholades, or File fish. Of both there are 

 several sorts ; but, by describing these two, 

 we shall have a competent idea of all the rest. 



On a slight view, the sea-urchin may be 

 compared to the husk of a chestnut; being, 

 like it, round, and with a number of bony 

 prickles standing out on every side. To 

 exhibit this extraordinary animal in every 

 light if we could conceive a turnip stuck full 

 of pins on every side, and running upon these 

 pins with some degree of swiftness, we should 

 have some idea of this extraordinary creature 

 The mouth is placed downwards ; the vent is 

 above; the shell is a hollow vase, resembling 

 a scooped apple ; and this filled with a soft 

 muscular substance, through which the intes- 

 tines wind from the bottom to the top. The 

 mouth, which is placed undermost, is large 

 and red, furnished with five sharp teeth, 

 which are easily discerned. The jaws are 

 strengthened by five small bones, in the 

 centre of which is a small fleshy tongue ; and 

 from this the intestines make a winding of 

 five spires, round the internal sides of the 

 shell, ending at the top, where the excrements 

 are excluded. But what makes the most ex- 

 traordinary part of this animal's conformation, 

 are its horns and its spines, that point from 

 every part of the body, like the horns of a 

 snail, and that serve at once as legs to move 

 upon, as arms to feel with, and as instruments 

 of capture and defence. Between these horns 

 it has also spines that are not endued with 

 such a share of motion. The spines and the 

 horns issue from every part of its body ; the 

 spines being hard and prickly; the horns 

 being soft, longer than the spines, and never 

 seen except in the water. They are put for- 

 ward and withdrawn like the horns of a snail, 

 and are hid in the bases of the spines, serving, 

 as was said before, for procuring food and 

 motion. All this apparatus, however, is only 

 seen when the animal is hunting its prey at 

 the bottom of the water; for a few minutes 

 after it is taken, all the horns are withdrawn 

 into the body, and most of the spines drop off. 



It is generally said of insects, that those 

 which have the greatest number of legs 

 always move the slowest ; but this animal 

 seems to be an exception to the rule ; for 

 though furnished with two thousand spines, 

 and twelve hundred horns, all serving for legs, 

 and from their number seeming to impede 

 each other's motion, yet it runs with some 

 share of swiftness at the bottom, and it is 

 sometimes no easy matter to overtake it. It 

 is often taken upon the ebb, by following it 

 in shallow water, either in an osier basket, 

 or simply with the hand. Both the spines 

 and the horns assist its motion ; and the ani- 

 rnal is usually seen running with the mouth 

 downward. 



