which Bosc supposed must have been wounded, re- 

 mained a week in a contracted state. 



These shells have been called by different names, 

 all however indicative of their form, such as wood-louse, 

 sea boat, rattle-snake's tail, lobster's tail, sea bug, and 

 sea caterpillar. The French say that the animal may be 

 eaten, and we are told that the Iceland fishers swallow 

 it raw to quench their thirst, and pretend that it is good 

 also against sea sickness. These shells are found, but 

 rarely in abundance, on the coasts of North and South 

 America, in the Straits of Magellan, on the coast of 

 Africa, in the West Indies, in Carolina, on the coasts of 

 France, England, &c. 



It must be observed, that the subjects of this genus, 

 before the time of Linnaeus, were scattered about in 

 authors, without being referred to any particular class ; 

 but the systematic plan of the great Swedish naturalist, 

 forced him to decide upon their situation, and he 

 accordingly gave them a place among the testaceous 

 multivalves. How far they are entitled to rank with 

 the shells, in preference to the marine insects, will cer- 

 tainly admit of dispute, since, unlike all other Testacea, 

 their valves are formed of an intermediate substance 

 between carbonate of lime and animal gluten. The fol- 

 lowing experiments will prove that this assertion is not 

 without foundation. 



A Chiton marginatus, weighing two grains, effervesced 

 strongly in muriatic acid, and lost seven-eights of its 

 weight ; the remainder was animal gluten, and retained 

 the perfect form of the shell. 



A valve of the Chiton squamosus weighing twenty 

 grains, lost in muriatic acid nine-tenths of its weight, 

 the animal part which was undissolved, retained (before 

 it was dried) the form and colour of the valve, the 



