278 



to its former depth. Tnere it continues secure; 

 no salt can allure it a second time ; but it remains 

 unmolested unless the fisher will beat the trouble of 

 digging it out, sometimes two ieet below the sur- 

 face. 



Multivalve shell-fish may be considered as aninaals 

 saut up in round boxes. To view their habitti>ns 

 externally, one would be little ap f to consi i -r them 

 as the retreats ot living creatures; and still less, ta 

 suppose that some of them carry thtir boxes with a 

 tolerable share of swiftness, so a-s to escape their 

 pursuers. Of these there are principally two kinds; 

 surh as move, and such as are stationary : the first are 

 usually known in our cabine s by the name of sea-eggs; 

 the others are often admired for the cavities which 

 they scoop out for their habitation in the hardest mar- 

 ble. The first are called, by naturalists, Ecnini, or 

 urchins : the latter are called Pholades., or filetish, 

 Of both these are several sorts ; but by describing 

 these two, we shall have a competent idea of all the 

 rest. 



To a slight view, the Sea-urchin may be compared 

 to tn- husk of a chesnut ; being like it, round and 

 Mfith a number of bony prickles standing out on every 

 side, if we could conceive a turnip stuck full of pins 

 on eveiy side, and running upon these pins with some 

 degree o! swiftness, we should have some idea of this 

 fx.raordiuary creature. The mouth is placed down* 

 waras ; the vent is above ; the shell is a hollow vase, 

 rese bltug a scooped apple; and this tilled with a 

 soft muscular substance, through which the intestines 

 \vind Irom th bottom to the top. The mouth, 

 which is placed undermost, is large and red, furnished 

 witii fi it Bnarp teetn. which are >asi1y discerned* 

 The jaws aie strengthened by fine small bones, in the 

 centre of winch is a small tieshy tongue ; and from 

 this the intestines make a winding o five spires, round 

 the internal sides of the shell) ending at the toj> r 



